# CVE-2026-33999: Xorg: xwayland: x.org x server: denial of service via integer underflow in xkb compatibility map handling

Status: published. Published: 2026-04-23. Updated: 2026-11-04.

A flaw was found in the X.Org X server. This integer underflow vulnerability, specifically in the XKB compatibility map handling, allows an attacker with local or remote X11 server access to trigger a buffer read overrun. This can lead to memory-safety violations and potentially a denial of service (DoS) or other severe impacts.

## Remediation

- workaround: To mitigate this issue, restrict access to the X11 server. For remote access, disable X11 forwarding in SSH configurations if not required. Edit `/etc/ssh/sshd_config` and set `X11Forwarding no`. After modifying the configuration, restart the `sshd` service using `systemctl restart sshd`. Disabling X11 forwarding may impact remote graphical applications. (source: CNA: redhat)
- fix: RHSA-2026:23496: Red Hat Enterprise Linux Server -EXTENSION(v. 6 ELS-EXTENSION), Red Hat Enterprise Linux Server Optional -EXTENSION (v. 6 ELS -EXTENSION)

RHSA-2026:22456: Red Hat Enterprise Linux Server (v. 7 ELS), Red Hat Enterprise Linux Server Optional (v. 7 ELS)

RHSA-2026:20590: Red Hat Enterprise Linux Server (v. 7 ELS), Red Hat Enterprise Linux Server Optional (v. 7 ELS)

RHSA-2026:20563: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)

RHSA-2026:11352: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)

RHSA-2026:19125: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)

RHSA-2026:13414: Red Hat Enterprise Linux AppStream (v. 8)

RHSA-2026:11692: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux CRB (v. 8)

RHSA-2026:11656: Red Hat Enterprise Linux AppStream (v. 8)

RHSA-2026:23254: Red Hat Enterprise Linux AppStream AUS (v.8.4), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4)

RHSA-2026:21715: Red Hat Enterprise Linux AppStream AUS (v.8.4), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4)

RHSA-2026:24341: Red Hat Enterprise Linux AppStream AUS (v.8.6), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)

RHSA-2026:21718: Red Hat Enterprise Linux AppStream AUS (v.8.6), Red Hat Enterprise Linux AppStream E4S (v.8.6), Red Hat Enterprise Linux AppStream TUS (v.8.6)

RHSA-2026:21716: Red Hat Enterprise Linux AppStream AUS (v.8.6), Red Hat Enterprise Linux AppStream E4S (v.8.6), Red Hat Enterprise Linux AppStream TUS (v.8.6)

RHSA-2026:23255: Red Hat Enterprise Linux AppStream E4S (v.8.8), Red Hat Enterprise Linux AppStream TUS (v.8.8)

RHSA-2026:21742: Red Hat Enterprise Linux AppStream E4S (v.8.8), Red Hat Enterprise Linux AppStream TUS (v.8.8)

RHSA-2026:21712: Red Hat Enterprise Linux AppStream E4S (v.8.8), Red Hat Enterprise Linux AppStream TUS (v.8.8)

RHSA-2026:21741: Red Hat Enterprise Linux AppStream E4S (v.9.0)

RHSA-2026:21699: Red Hat Enterprise Linux AppStream E4S (v.9.0)

RHSA-2026:20562: Red Hat Enterprise Linux AppStream E4S (v.9.0)

RHSA-2026:20576: Red Hat Enterprise Linux AppStream E4S (v.9.2)

RHSA-2026:20557: Red Hat Enterprise Linux AppStream E4S (v.9.2)

RHSA-2026:20547: Red Hat Enterprise Linux AppStream E4S (v.9.2)

RHSA-2026:20575: Red Hat Enterprise Linux AppStream EUS (v.9.4)

RHSA-2026:20555: Red Hat CodeReady Linux Builder EUS (v.9.4), Red Hat Enterprise Linux AppStream EUS (v.9.4)

RHSA-2026:20560: Red Hat Enterprise Linux AppStream EUS (v.9.4)

RHSA-2026:22424: Red Hat Enterprise Linux AppStream EUS (v.9.6)

RHSA-2026:20558: Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux AppStream EUS (v.9.6)

RHSA-2026:20561: Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux AppStream EUS (v.9.6)

RHSA-2026:10739: Red Hat Enterprise Linux AppStream (v. 9)

RHSA-2026:11388: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)

RHSA-2026:11369: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)

RHSA-2026:19342: Red Hat Enterprise Linux AppStream (v. 9)

RHSA-2026:19343: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)

RHSA-2026:19344: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) (source: ADP: redhat-SADP)
- workaround: To mitigate this issue, restrict access to the X11 server. For remote access, disable X11 forwarding in SSH configurations if not required. Edit `/etc/ssh/sshd_config` and set `X11Forwarding no`. After modifying the configuration, restart the `sshd` service using `systemctl restart sshd`. Disabling X11 forwarding may impact remote graphical applications. (source: ADP: redhat-SADP)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 10 (xorg-x11-server-Xwayland): ≥ 0:24.1.5-6.el10_1; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10 (xorg-x11-server-Xwayland): ≥ 0:24.1.9-4.el10_2; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10.0 Extended Update Support (xorg-x11-server-Xwayland): ≥ 0:24.1.5-6.el10_0; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 Extended Lifecycle Support  - EXTENSION (tigervnc): ≥ 0:1.1.0-25.el6_10.16; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 Extended Lifecycle Support (xorg-x11-server): ≥ 0:1.20.4-34.el7_9; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 Extended Lifecycle Support (tigervnc): ≥ 0:1.8.0-36.el7_9.4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (xorg-x11-server-Xwayland): ≥ 0:21.1.3-20.el8_10; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (xorg-x11-server): ≥ 0:1.20.11-28.el8_10; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (tigervnc): ≥ 0:1.15.0-9.el8_10; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (xorg-x11-server): ≥ 0:1.20.10-4.el8_4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (tigervnc): ≥ 0:1.11.0-8.el8_4.15; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (xorg-x11-server): ≥ 0:1.20.10-4.el8_4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (tigervnc): ≥ 0:1.11.0-8.el8_4.15; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (xorg-x11-server-Xwayland): ≥ 0:21.1.3-2.el8_6.6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (xorg-x11-server): ≥ 0:1.20.11-7.el8_6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (tigervnc): ≥ 0:1.12.0-6.el8_6.17; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On (tigervnc): ≥ 0:1.12.0-6.el8_6.17; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Telecommunications Update Service (xorg-x11-server-Xwayland): ≥ 0:21.1.3-2.el8_6.6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Telecommunications Update Service (xorg-x11-server): ≥ 0:1.20.11-7.el8_6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions (xorg-x11-server-Xwayland): ≥ 0:21.1.3-2.el8_6.6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions (xorg-x11-server): ≥ 0:1.20.11-7.el8_6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service (xorg-x11-server-Xwayland): ≥ 0:21.1.3-13.el8_8; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service (xorg-x11-server): ≥ 0:1.20.11-18.el8_8; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service (tigervnc): ≥ 0:1.12.0-15.el8_8.17; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (xorg-x11-server-Xwayland): ≥ 0:21.1.3-13.el8_8; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (xorg-x11-server): ≥ 0:1.20.11-18.el8_8; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (tigervnc): ≥ 0:1.12.0-15.el8_8.17; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (tigervnc): ≥ 0:1.15.0-6.el9_7.1; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (xorg-x11-server-Xwayland): ≥ 0:23.2.7-6.el9_7; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (xorg-x11-server): ≥ 0:1.20.11-33.el9_7; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (tigervnc): ≥ 0:1.15.0-7.el9_8.1; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (xorg-x11-server): ≥ 0:1.20.11-34.el9_8; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (xorg-x11-server-Xwayland): ≥ 0:24.1.9-4.el9_8; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions (xorg-x11-server-Xwayland): ≥ 0:21.1.3-5.el9_0; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions (xorg-x11-server): ≥ 0:1.20.11-13.el9_0; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions (tigervnc): ≥ 0:1.11.0-22.el9_0.17; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (xorg-x11-server-Xwayland): ≥ 0:21.1.3-10.el9_2; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (xorg-x11-server): ≥ 0:1.20.11-20.el9_2; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (tigervnc): ≥ 0:1.12.0-14.el9_2.14; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support (xorg-x11-server): ≥ 0:1.20.11-28.el9_4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support (xorg-x11-server-Xwayland): ≥ 0:22.1.9-8.el9_4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support (tigervnc): ≥ 0:1.13.1-8.el9_4.9; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.6 Extended Update Support (xorg-x11-server): ≥ 0:1.20.11-33.el9_6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.6 Extended Update Support (xorg-x11-server-Xwayland): ≥ 0:23.2.7-6.el9_6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.6 Extended Update Support (tigervnc): ≥ 0:1.14.1-10.el9_6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (xorg-x11-server): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10 (xorg-x11-server-Xwayland): ≥ 0:24.1.5-6.el10_1; < * (unaffected, rpm); ≥ 0:24.1.9-4.el10_2; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 10.0 Extended Update Support (xorg-x11-server-Xwayland): ≥ 0:24.1.5-6.el10_0; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 6 Extended Lifecycle Support  - EXTENSION (tigervnc): ≥ 0:1.1.0-25.el6_10.16; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 7 Extended Lifecycle Support (xorg-x11-server): ≥ 0:1.20.4-34.el7_9; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 7 Extended Lifecycle Support (tigervnc): ≥ 0:1.8.0-36.el7_9.4; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8 (xorg-x11-server-Xwayland): ≥ 0:21.1.3-20.el8_10; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8 (xorg-x11-server): ≥ 0:1.20.11-28.el8_10; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8 (tigervnc): ≥ 0:1.15.0-9.el8_10; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (xorg-x11-server): ≥ 0:1.20.10-4.el8_4; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (tigervnc): ≥ 0:1.11.0-8.el8_4.15; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (xorg-x11-server): ≥ 0:1.20.10-4.el8_4; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (tigervnc): ≥ 0:1.11.0-8.el8_4.15; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (xorg-x11-server-Xwayland): ≥ 0:21.1.3-2.el8_6.6; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (xorg-x11-server): ≥ 0:1.20.11-7.el8_6; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (tigervnc): ≥ 0:1.12.0-6.el8_6.17; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On (tigervnc): ≥ 0:1.12.0-6.el8_6.17; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.6 Telecommunications Update Service (xorg-x11-server-Xwayland): ≥ 0:21.1.3-2.el8_6.6; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.6 Telecommunications Update Service (xorg-x11-server): ≥ 0:1.20.11-7.el8_6; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions (xorg-x11-server-Xwayland): ≥ 0:21.1.3-2.el8_6.6; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions (xorg-x11-server): ≥ 0:1.20.11-7.el8_6; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service (xorg-x11-server-Xwayland): ≥ 0:21.1.3-13.el8_8; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service (xorg-x11-server): ≥ 0:1.20.11-18.el8_8; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service (tigervnc): ≥ 0:1.12.0-15.el8_8.17; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (xorg-x11-server-Xwayland): ≥ 0:21.1.3-13.el8_8; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (xorg-x11-server): ≥ 0:1.20.11-18.el8_8; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (tigervnc): ≥ 0:1.12.0-15.el8_8.17; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9 (tigervnc): ≥ 0:1.15.0-6.el9_7.1; < * (unaffected, rpm); ≥ 0:1.15.0-7.el9_8.1; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9 (xorg-x11-server-Xwayland): ≥ 0:23.2.7-6.el9_7; < * (unaffected, rpm); ≥ 0:24.1.9-4.el9_8; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9 (xorg-x11-server): ≥ 0:1.20.11-33.el9_7; < * (unaffected, rpm); ≥ 0:1.20.11-34.el9_8; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions (xorg-x11-server-Xwayland): ≥ 0:21.1.3-5.el9_0; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions (xorg-x11-server): ≥ 0:1.20.11-13.el9_0; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions (tigervnc): ≥ 0:1.11.0-22.el9_0.17; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (xorg-x11-server-Xwayland): ≥ 0:21.1.3-10.el9_2; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (xorg-x11-server): ≥ 0:1.20.11-20.el9_2; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (tigervnc): ≥ 0:1.12.0-14.el9_2.14; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support (xorg-x11-server): ≥ 0:1.20.11-28.el9_4; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support (xorg-x11-server-Xwayland): ≥ 0:22.1.9-8.el9_4; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support (tigervnc): ≥ 0:1.13.1-8.el9_4.9; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.6 Extended Update Support (xorg-x11-server): ≥ 0:1.20.11-33.el9_6; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.6 Extended Update Support (xorg-x11-server-Xwayland): ≥ 0:23.2.7-6.el9_6; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.6 Extended Update Support (tigervnc): ≥ 0:1.14.1-10.el9_6; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 6 (xorg-x11-server): Version range not reported. Source: ADP: redhat-SADP

## Severity and prioritization

- CVSS 3.1: 7.8 (high); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H; source: CNA: redhat

- CVSS 3.1: 7.8 (high); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H; source: ADP: redhat-SADP

- CVSS 3.1: 7.8 (high); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H; source: NVD: secalert@redhat.com

- CVSS 3.1: 7.8 (high); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H; source: NVD: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

- CISA KEV: No listing in collected sources

- EPSS: 0.38% as of 2026-11-04; percentile 32.19%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-191

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/errata/RHSA-2026:10739 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:11352 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:11369 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:11388 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:11656 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:11692 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:13414 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:19125 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:19342 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:19343 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:19344 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20547 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20555 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20557 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20558 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20560 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20561 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20562 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20563 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20575 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20576 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20590 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21699 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21712 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21715 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21716 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21718 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21741 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21742 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:22424 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:22456 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:23254 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:23255 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:23496 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:24341 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-33999 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2451106 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-33999 (ADP: redhat-SADP; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2451106 (ADP: redhat-SADP; issue-tracking, x_refsource_REDHAT)

- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33999.json (ADP: redhat-SADP; x_sadp-csaf-vex)

- https://access.redhat.com/errata/RHSA-2026:23496 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:22456 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20590 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20563 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:11352 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:19125 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:13414 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:11692 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:11656 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:23254 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21715 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:24341 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21718 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21716 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:23255 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21742 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21712 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21741 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:21699 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20562 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20576 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20557 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20547 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20575 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20555 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20560 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:22424 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20558 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:20561 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:10739 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:11388 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:11369 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:19342 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:19343 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:19344 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:10739 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:11352 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:11369 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:11388 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:11656 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:11692 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:13414 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:19125 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:19342 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:19343 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:19344 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:20547 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:20555 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:20557 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:20558 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:20560 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:20561 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:20562 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:20563 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:20575 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:20576 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:20590 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:21699 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:21712 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:21715 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:21716 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:21718 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:21741 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:21742 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:22424 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:22456 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:23254 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:23255 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:23496 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:24341 (secalert@redhat.com)

- https://access.redhat.com/security/cve/CVE-2026-33999 (secalert@redhat.com)

- https://bugzilla.redhat.com/show_bug.cgi?id=2451106 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:10739 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:11352 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:11369 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:11388 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:11656 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:11692 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:13414 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:19125 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:19342 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:19343 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:19344 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:20547 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:20555 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:20557 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:20558 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:20560 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:20561 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:20562 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:20563 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:20575 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:20576 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:20590 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:21699 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:21712 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:21715 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:21716 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:21718 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:21741 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:21742 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:22424 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:22456 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:23254 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:23255 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:23496 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:24341 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/security/cve/CVE-2026-33999 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://bugzilla.redhat.com/show_bug.cgi?id=2451106 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33999.json (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-33999; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33999; retrieved 2026-11-05; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-33999; retrieved 2026-11-04; source updated Not reported

Revision: 972cf874ddfe736cf7655858a1c115652d87b4988feb02a8f746c9c43e15b085

Canonical: https://y2.dev/cve/CVE-2026-33999

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.