# CVE-2025-26595: Xorg: xwayland: buffer overflow in xkbvmodmasktext() Status: published. Published: 2025-02-25. Updated: 2026-11-04. A buffer overflow flaw was found in X.Org and Xwayland. The code in XkbVModMaskText() allocates a fixed-sized buffer on the stack and copies the names of the virtual modifiers to that buffer. The code fails to check the bounds of the buffer and would copy the data regardless of the size. ## Remediation - workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. (source: CNA: redhat) ## Affected products and versions - / (xserver): ≥ 0; < 21.1.16 (affected, semver); ≥ 22.0.0; < 24.1.6 (affected, semver). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 10 (xorg-x11-server-Xwayland): ≥ 0:24.1.5-3.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; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 7 Extended Lifecycle Support (tigervnc): ≥ 0:1.8.0-36.el7_9; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 7 Extended Lifecycle Support (xorg-x11-server): ≥ 0:1.20.4-30.el7_9; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 8 (tigervnc): ≥ 0:1.13.1-15.el8_10; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 8.2 Advanced Update Support (tigervnc): ≥ 0:1.9.0-15.el8_2.13; < * (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_4.12; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 8.4 Telecommunications Update Service (tigervnc): ≥ 0:1.11.0-8.el8_4.12; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions (tigervnc): ≥ 0:1.11.0-8.el8_4.12; < * (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_6.13; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 8.6 Telecommunications Update Service (tigervnc): ≥ 0:1.12.0-6.el8_6.13; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions (tigervnc): ≥ 0:1.12.0-6.el8_6.13; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 8.8 Extended Update Support (tigervnc): ≥ 0:1.12.0-15.el8_8.12; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 9 (tigervnc): ≥ 0:1.14.1-1.el9_5.1; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 9 (xorg-x11-server): ≥ 0:1.20.11-28.el9_6; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 9 (xorg-x11-server-Xwayland): ≥ 0:23.2.7-3.el9_6; < * (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_0.13; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 9.2 Extended Update Support (tigervnc): ≥ 0:1.12.0-14.el9_2.10; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support (tigervnc): ≥ 0:1.13.1-8.el9_4.5; < * (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 8 (xorg-x11-server): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat Enterprise Linux 8 (xorg-x11-server-Xwayland): Version range not reported. Source: CNA: redhat ## NVD configuration conditions Affected CPE matches depend on the following AND/OR and negation conditions: ```json [ { "negate": false, "nodes": [ { "cpeMatch": [ { "criteria": "cpe:2.3:a:tigervnc:tigervnc:-:*:*:*:*:*:*:*", "vulnerable": true } ], "negate": false, "operator": "OR" } ], "operator": "OR" }, { "negate": false, "nodes": [ { "cpeMatch": [ { "criteria": "cpe:2.3:a:x.org:x_server:*:*:*:*:*:*:*:*", "versionEndExcluding": "21.1.16", "vulnerable": true }, { "criteria": "cpe:2.3:a:x.org:xwayland:*:*:*:*:*:*:*:*", "versionEndExcluding": "24.1.6", "vulnerable": true } ], "negate": false, "operator": "OR" } ], "operator": "OR" }, { "negate": false, "nodes": [ { "cpeMatch": [ { "criteria": "cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*", "vulnerable": true }, { "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*", "vulnerable": true }, { "criteria": "cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*", "vulnerable": true } ], "negate": false, "operator": "OR" } ], "operator": "OR" } ] ``` ## 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: NVD: nvd@nist.gov - 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 - CISA KEV: No listing in collected sources - EPSS: 0.44% as of 2026-11-04; percentile 38.17% - SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP - Weaknesses: CWE-121, CWE-787 ## Exploit evidence No exploit evidence in collected sources. This is not proof of no exploitation. ## References - https://access.redhat.com/errata/RHSA-2025:2500 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:2502 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:2861 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:2862 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:2865 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:2866 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:2873 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:2874 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:2875 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:2879 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:2880 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:3976 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:7163 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:7165 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2025:7458 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/security/cve/CVE-2025-26595 (CNA: redhat; vdb-entry, x_refsource_REDHAT) - https://bugzilla.redhat.com/show_bug.cgi?id=2345257 (CNA: redhat; issue-tracking, x_refsource_REDHAT) - https://lists.debian.org/debian-lts-announce/2025/02/msg00036.html (ADP: CVE) - https://access.redhat.com/errata/RHSA-2025:2500 (secalert@redhat.com; Third Party Advisory) - https://access.redhat.com/errata/RHSA-2025:2502 (secalert@redhat.com; Third Party Advisory) - https://access.redhat.com/errata/RHSA-2025:2861 (secalert@redhat.com; Third Party Advisory) - https://access.redhat.com/errata/RHSA-2025:2862 (secalert@redhat.com; Third Party Advisory) - https://access.redhat.com/errata/RHSA-2025:2865 (secalert@redhat.com; Third Party Advisory) - https://access.redhat.com/errata/RHSA-2025:2866 (secalert@redhat.com; Third Party Advisory) - https://access.redhat.com/errata/RHSA-2025:2873 (secalert@redhat.com; Third Party Advisory) - https://access.redhat.com/errata/RHSA-2025:2874 (secalert@redhat.com; Third Party Advisory) - https://access.redhat.com/errata/RHSA-2025:2875 (secalert@redhat.com; Third Party Advisory) - https://access.redhat.com/errata/RHSA-2025:2879 (secalert@redhat.com; Third Party Advisory) - https://access.redhat.com/errata/RHSA-2025:2880 (secalert@redhat.com; Third Party Advisory) - https://access.redhat.com/errata/RHSA-2025:3976 (secalert@redhat.com) - https://access.redhat.com/errata/RHSA-2025:7163 (secalert@redhat.com) - https://access.redhat.com/errata/RHSA-2025:7165 (secalert@redhat.com) - https://access.redhat.com/errata/RHSA-2025:7458 (secalert@redhat.com) - https://access.redhat.com/security/cve/CVE-2025-26595 (secalert@redhat.com; Third Party Advisory) - https://bugzilla.redhat.com/show_bug.cgi?id=2345257 (secalert@redhat.com; Issue Tracking) - https://lists.debian.org/debian-lts-announce/2025/02/msg00036.html (af854a3a-2127-422b-91ae-364da2661108) ## Provenance - CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2025-26595; retrieved 2026-11-04; source updated 2026-11-04 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-26595; retrieved 2026-11-05; source updated 2026-11-04 - FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2025-26595; retrieved 2026-11-04; source updated Not reported Revision: 2f57ea14c20a8e9c44ee639cc79b606ac72ddd66af89a306d1d1c268c938f33f Canonical: https://y2.dev/cve/CVE-2025-26595 ## 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. 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