# CVE-2026-59691: Gstreamer1-plugins-bad-free: gstreamer: rfbsrc/librfb hextile heap out-of-bounds write with 16bpp framebuffer

Status: published. Published: 2026-07-09. Updated: 2026-11-04.

A heap buffer overflow vulnerability was found in GStreamer's rfbsrc plugin. When a client connects to a malicious RFB/VNC server that advertises a 16bpp framebuffer and sends Hextile-encoded updates, the Hextile background fill path writes 32-bit pixel values into a buffer allocated for 16-bit pixels. This type mismatch causes an out-of-bounds heap write that can lead to denial of service (process crash) and potential memory corruption.

## Remediation

- workaround: There is no complete mitigation for this vulnerability. The following measures can reduce risk:

1. Do not connect GStreamer pipelines using rfbsrc to untrusted or unknown VNC servers.
2. If the rfbsrc plugin is not required, remove the librfb plugin shared object from the GStreamer plugins directory (typically /usr/lib64/gstreamer-1.0/libgstrfbsrc.so).
3. Network-level controls (firewall rules) can restrict outbound VNC connections to trusted servers only. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 10 (gstreamer1-plugins-bad-free): ≥ 0:1.26.7-2.el10_2.6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10.0 Extended Update Support (gstreamer1-plugins-bad-free): ≥ 0:1.24.11-3.el10_0.6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 Extended Lifecycle Support (gstreamer1-plugins-bad-free): ≥ 0:1.10.4-7.el7_9; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 Extended Lifecycle Support (gstreamer-plugins-bad-free): ≥ 0:0.10.23-26.el7_9; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (gstreamer1-plugins-bad-free): ≥ 0:1.16.1-9.el8_10.1; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (gstreamer1-plugins-bad-free): ≥ 0:1.16.1-4.el8_4.4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (gstreamer1-plugins-bad-free): ≥ 0:1.16.1-4.el8_4.4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (gstreamer1-plugins-bad-free): ≥ 0:1.16.1-4.el8_6.4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On (gstreamer1-plugins-bad-free): ≥ 0:1.16.1-4.el8_6.4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service (gstreamer1-plugins-bad-free): ≥ 0:1.16.1-4.el8_8.4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (gstreamer1-plugins-bad-free): ≥ 0:1.16.1-4.el8_8.4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (gstreamer1-plugins-bad-free): ≥ 0:1.22.12-7.el9_8.3; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (gstreamer1-plugins-bad-free): ≥ 0:1.18.4-9.el9_2.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions (gstreamer1-plugins-bad-free): ≥ 0:1.22.1-6.el9_4.6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.6 Extended Update Support (gstreamer1-plugins-bad-free): ≥ 0:1.22.12-5.el9_6.6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (gstreamer-plugins-bad-free): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 7.1 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H; source: CNA: redhat

- CVSS 3.1: 7.1 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H; source: NVD: secalert@redhat.com

- CISA KEV: No listing in collected sources

- EPSS: 0.33% as of 2026-11-04; percentile 25.79%

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

- Weaknesses: CWE-787

## Exploit evidence

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

## References

- https://access.redhat.com/errata/RHSA-2026:47179 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:47180 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:47731 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:54658 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:54659 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:54660 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:54664 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:54665 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:54752 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:56658 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:56772 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:62532 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-59691 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2497343 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://gitlab.freedesktop.org/gstreamer/gstreamer-security/-/merge_requests/100 (CNA: redhat)

- https://gitlab.freedesktop.org/gstreamer/gstreamer/-/work_items/5173 (CNA: redhat)

- https://access.redhat.com/errata/RHSA-2026:47179 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:47180 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:47731 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:54658 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:54659 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:54660 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:54664 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:54665 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:54752 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:56658 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:56772 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:62532 (secalert@redhat.com)

- https://access.redhat.com/security/cve/CVE-2026-59691 (secalert@redhat.com)

- https://bugzilla.redhat.com/show_bug.cgi?id=2497343 (secalert@redhat.com)

- https://gitlab.freedesktop.org/gstreamer/gstreamer-security/-/merge_requests/100 (secalert@redhat.com)

- https://gitlab.freedesktop.org/gstreamer/gstreamer/-/work_items/5173 (secalert@redhat.com)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-59691; retrieved 2026-11-05; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-59691; retrieved 2026-11-05; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-59691; retrieved 2026-11-05; source updated Not reported

Revision: dab73842ad3f9beba5d13d579befa9228b14159ecedd0c442ac79b5a49dea970

Canonical: https://y2.dev/cve/CVE-2026-59691

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