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Fencer Vulns
high 7.8

CVE-2025-26596 json

Xorg: xwayland: heap overflow in xkbwritekeysyms()

published 2025-02-25 20 mo ago modified 2026-11-04 4 d ago also EUVD-2025-5403

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

A heap overflow flaw was found in X.Org and Xwayland. The computation of the length in XkbSizeKeySyms() differs from what is written in XkbWriteKeySyms(), which may lead to a heap-based buffer overflow.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 10 0:24.1.5-3.el10_0
  • Red Hat Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION 0:1.1.0-25.el6_10
  • Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support 0:1.8.0-36.el7_9, 0:1.20.4-30.el7_9
  • Red Hat Red Hat Enterprise Linux 8 0:1.13.1-15.el8_10
  • Red Hat Red Hat Enterprise Linux 8.2 Advanced Update Support 0:1.9.0-15.el8_2.13
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 0:1.11.0-8.el8_4.12
  • Red Hat Red Hat Enterprise Linux 8.4 Telecommunications Update Service 0:1.11.0-8.el8_4.12
  • Red Hat Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions 0:1.11.0-8.el8_4.12
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 0:1.12.0-6.el8_6.13
  • Red Hat Red Hat Enterprise Linux 8.6 Telecommunications Update Service 0:1.12.0-6.el8_6.13
  • Red Hat Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions 0:1.12.0-6.el8_6.13
  • Red Hat Red Hat Enterprise Linux 8.8 Extended Update Support 0:1.12.0-15.el8_8.12
  • Red Hat Red Hat Enterprise Linux 9 0:1.14.1-1.el9_5.1, 0:1.20.11-28.el9_6, 0:23.2.7-3.el9_6
  • Red Hat Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions 0:1.11.0-22.el9_0.13
  • Red Hat Red Hat Enterprise Linux 9.2 Extended Update Support 0:1.12.0-14.el9_2.10
  • Red Hat Red Hat Enterprise Linux 9.4 Extended Update Support 0:1.13.1-8.el9_4.5
  • xwayland Debian 14, Debian 13 2:24.1.6-1
  • xorg-server Debian 12 2:21.1.7-3+deb12u9
  • xorg-server Debian 14, Debian 13 2:21.1.16-1

debian advisories DEBIAN-CVE-2025-26596

  • xwayland Ubuntu 22.04 LTS 2:22.1.1-1ubuntu0.17
  • xwayland Ubuntu 24.04 LTS 2:23.2.6-1ubuntu0.4
  • xorg-server Ubuntu 20.04 LTS 2:1.20.13-1ubuntu1~20.04.19
  • xorg-server Ubuntu 22.04 LTS 2:21.1.4-2ubuntu1.7~22.04.13
  • xorg-server Ubuntu 24.04 LTS 2:21.1.12-1ubuntu1.2
  • xorg-server Ubuntu 25.10 2:21.1.16-1ubuntu1
  • xorg-server Ubuntu Pro 16.04 LTS 2:1.18.4-0ubuntu0.12+esm17
  • xorg-server Ubuntu Pro 18.04 LTS 2:1.19.6-1ubuntu4.15+esm12

ubuntu advisories UBUNTU-CVE-2025-26596

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • xorg-x11-server-Xwayland RHEL 10.0 24.1.5-3.el10_0
  • xorg-x11-server RHEL 9 1.20.11-28.el9_6
  • xorg-x11-server-Xdmx RHEL 9 1.20.11-28.el9_6
  • xorg-x11-server-Xorg RHEL 9 1.20.11-28.el9_6
  • xorg-x11-server-Xvfb RHEL 9 1.20.11-28.el9_6
  • xorg-x11-server-Xnest RHEL 9 1.20.11-28.el9_6
  • xorg-x11-server-common RHEL 9 1.20.11-28.el9_6
  • xorg-x11-server-source RHEL 9 1.20.11-28.el9_6

red hat advisories RHSA-2025:3976RHSA-2025:7458RHSA-2025:7163RHSA-2025:7165RHSA-2025:2879RHSA-2025:2880

  • xorg-x11-server SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE Workstation Extension 15 SP6 +2 more 1.20.3-150200.22.5.102.1
  • xorg-x11-server SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +3 more 1.20.3-150400.38.54.1
  • xorg-x11-server SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 21.1.4-150500.7.32.1
  • xorg-x11-server SLE Module for Development Tools 15 SP6, SLE Module for Basesystem 15 SP6, openSUSE Leap 15.6 21.1.11-150600.5.6.1
  • xwayland SLE Workstation Extension 15 SP6, openSUSE Leap 15.6 24.1.1-150600.5.9.1
  • xorg-x11-server SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 1.19.6-10.80.1

suse advisories SUSE-SU-2025:0734-1SUSE-SU-2025:0733-1SUSE-SU-2025:0732-1SUSE-SU-2025:0731-1SUSE-SU-2025:0730-1SUSE-SU-2025:0729-1

  • xorg-x11-server openSUSE Tumbleweed 21.1.15-2.1
  • xwayland openSUSE Tumbleweed 24.1.5-2.1

opensuse advisories openSUSE-SU-2025:14841-1openSUSE-SU-2025:14842-1

  • xorg-x11-server-Xdmx AlmaLinux 9 1.20.11-28.el9_6
  • xorg-x11-server-Xorg AlmaLinux 9 1.20.11-28.el9_6
  • xorg-x11-server-Xvfb AlmaLinux 9 1.20.11-28.el9_6
  • xorg-x11-server-Xnest AlmaLinux 9 1.20.11-28.el9_6
  • xorg-x11-server-common AlmaLinux 9 1.20.11-28.el9_6
  • xorg-x11-server-source AlmaLinux 9 1.20.11-28.el9_6
  • xorg-x11-server-Xephyr AlmaLinux 9 1.20.11-28.el9_6
  • xorg-x11-server-Xwayland AlmaLinux 9 23.2.7-3.el9_6

almalinux advisories ALSA-2025:7163ALSA-2025:7165ALSA-2025:2500ALSA-2025:2502

  • xorg-x11-server Rocky Linux 9 1.20.11-28.el9_6
  • xorg-x11-server-Xwayland Rocky Linux 9 23.2.7-3.el9_6
  • xorg-x11-server-Xwayland Rocky Linux 10 24.1.5-3.el10_0
  • tigervnc Rocky Linux 9 1.14.1-1.el9_5.1
  • tigervnc Rocky Linux 8 1.13.1-15.el8_10

rocky linux advisories RLSA-2025:7163RLSA-2025:7165RLSA-2025:7458RLSA-2025:2500RLSA-2025:2502

  • xorg-x11-server CBL-Mariner 2.0 1.20.10-15
  • xorg-x11-server-Xwayland Azure Linux 3.0 24.1.6-1

azure linux advisories AZL-57404AZL-57414

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-26596 updated cvss 7.8

xorg: xwayland: Heap overflow in XkbWriteKeySyms()

  • Red Hat Enterprise Linux 6 xorg-x11-server, xorg-x11-server-Xdmx, xorg-x11-server-Xorg, xorg-x11-server-Xvfb, xorg-x11-server-Xnest, xorg-x11-server-common, +2 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) tigervnc 1.13.1-15.el8_10, tigervnc-icons 1.13.1-15.el8_10, tigervnc-server 1.13.1-15.el8_10, tigervnc-license 1.13.1-15.el8_10, tigervnc-selinux 1.13.1-15.el8_10, tigervnc-server-module 1.13.1-15.el8_10, +1 more
    fixed: vendor fix RHSA-2025:2502
  • Red Hat Enterprise Linux AppStream (v. 9) tigervnc 1.14.1-1.el9_5.1, tigervnc-icons 1.14.1-1.el9_5.1, tigervnc-server 1.14.1-1.el9_5.1, xorg-x11-server 1.20.11-28.el9_6, tigervnc-license 1.14.1-1.el9_5.1, tigervnc-selinux 1.14.1-1.el9_5.1, +9 more
    fixed: vendor fix RHSA-2025:2500
  • Red Hat Enterprise Linux AppStream (v. 10) xorg-x11-server-Xwayland 24.1.5-3.el10_0
    fixed: vendor fix RHSA-2025:7458
  • Red Hat Enterprise Linux AppStream AUS (v. 8.2) tigervnc 1.9.0-15.el8_2.13, tigervnc-icons 1.9.0-15.el8_2.13, tigervnc-server 1.9.0-15.el8_2.13, tigervnc-license 1.9.0-15.el8_2.13, tigervnc-server-applet 1.9.0-15.el8_2.13, tigervnc-server-module 1.9.0-15.el8_2.13, +1 more
    fixed: vendor fix RHSA-2025:2866
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) tigervnc 1.11.0-8.el8_4.12, tigervnc-icons 1.11.0-8.el8_4.12, tigervnc-server 1.11.0-8.el8_4.12, tigervnc-license 1.11.0-8.el8_4.12, tigervnc-selinux 1.11.0-8.el8_4.12, tigervnc-server-module 1.11.0-8.el8_4.12, +1 more
    fixed: vendor fix RHSA-2025:2865
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) tigervnc 1.12.0-6.el8_6.13, tigervnc-icons 1.12.0-6.el8_6.13, tigervnc-server 1.12.0-6.el8_6.13, tigervnc-license 1.12.0-6.el8_6.13, tigervnc-selinux 1.12.0-6.el8_6.13, tigervnc-server-module 1.12.0-6.el8_6.13, +1 more
    fixed: vendor fix RHSA-2025:2880
  • Red Hat Enterprise Linux AppStream E4S (v.8.4) tigervnc 1.11.0-8.el8_4.12, tigervnc-icons 1.11.0-8.el8_4.12, tigervnc-server 1.11.0-8.el8_4.12, tigervnc-license 1.11.0-8.el8_4.12, tigervnc-selinux 1.11.0-8.el8_4.12, tigervnc-server-module 1.11.0-8.el8_4.12, +1 more
    fixed: vendor fix RHSA-2025:2865
show 14 more
  • Red Hat Enterprise Linux AppStream E4S (v.8.6) tigervnc 1.12.0-6.el8_6.13, tigervnc-icons 1.12.0-6.el8_6.13, tigervnc-server 1.12.0-6.el8_6.13, tigervnc-license 1.12.0-6.el8_6.13, tigervnc-selinux 1.12.0-6.el8_6.13, tigervnc-server-module 1.12.0-6.el8_6.13, +1 more
    fixed: vendor fix RHSA-2025:2880
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) tigervnc 1.11.0-22.el9_0.13, tigervnc-icons 1.11.0-22.el9_0.13, tigervnc-server 1.11.0-22.el9_0.13, tigervnc-license 1.11.0-22.el9_0.13, tigervnc-selinux 1.11.0-22.el9_0.13, tigervnc-server-module 1.11.0-22.el9_0.13, +1 more
    fixed: vendor fix RHSA-2025:2873
  • Red Hat Enterprise Linux AppStream EUS (v.8.8) tigervnc 1.12.0-15.el8_8.12, tigervnc-icons 1.12.0-15.el8_8.12, tigervnc-server 1.12.0-15.el8_8.12, tigervnc-license 1.12.0-15.el8_8.12, tigervnc-selinux 1.12.0-15.el8_8.12, tigervnc-server-module 1.12.0-15.el8_8.12, +1 more
    fixed: vendor fix RHSA-2025:2862
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) tigervnc 1.12.0-14.el9_2.10, tigervnc-icons 1.12.0-14.el9_2.10, tigervnc-server 1.12.0-14.el9_2.10, tigervnc-license 1.12.0-14.el9_2.10, tigervnc-selinux 1.12.0-14.el9_2.10, tigervnc-server-module 1.12.0-14.el9_2.10, +1 more
    fixed: vendor fix RHSA-2025:2874
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) tigervnc 1.13.1-8.el9_4.5, tigervnc-icons 1.13.1-8.el9_4.5, tigervnc-server 1.13.1-8.el9_4.5, tigervnc-license 1.13.1-8.el9_4.5, tigervnc-selinux 1.13.1-8.el9_4.5, tigervnc-server-module 1.13.1-8.el9_4.5, +1 more
    fixed: vendor fix RHSA-2025:2875
  • Red Hat Enterprise Linux AppStream TUS (v.8.4) tigervnc 1.11.0-8.el8_4.12, tigervnc-icons 1.11.0-8.el8_4.12, tigervnc-server 1.11.0-8.el8_4.12, tigervnc-license 1.11.0-8.el8_4.12, tigervnc-selinux 1.11.0-8.el8_4.12, tigervnc-server-module 1.11.0-8.el8_4.12, +1 more
    fixed: vendor fix RHSA-2025:2865
  • Red Hat Enterprise Linux AppStream TUS (v.8.6) tigervnc 1.12.0-6.el8_6.13, tigervnc-icons 1.12.0-6.el8_6.13, tigervnc-server 1.12.0-6.el8_6.13, tigervnc-license 1.12.0-6.el8_6.13, tigervnc-selinux 1.12.0-6.el8_6.13, tigervnc-server-module 1.12.0-6.el8_6.13, +1 more
    fixed: vendor fix RHSA-2025:2880
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) xorg-x11-server-source 1.20.11-28.el9_6, xorg-x11-server-Xwayland 23.2.7-3.el9_6
    fixed: vendor fix RHSA-2025:7163
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) xorg-x11-server-Xwayland-devel 24.1.5-3.el10_0, xorg-x11-server-Xwayland-debuginfo 24.1.5-3.el10_0, xorg-x11-server-Xwayland-debugsource 24.1.5-3.el10_0
    fixed: vendor fix RHSA-2025:7458
  • Red Hat Enterprise Linux Server -EXTENSION(v. 6 ELS-EXTENSION) tigervnc 1.1.0-25.el6_10, tigervnc-server 1.1.0-25.el6_10
    fixed: vendor fix RHSA-2025:3976
  • Red Hat Enterprise Linux Server (v. 7 ELS) tigervnc 1.8.0-36.el7_9, tigervnc-icons 1.8.0-36.el7_9, tigervnc-server 1.8.0-36.el7_9, tigervnc-license 1.8.0-36.el7_9, xorg-x11-server 1.20.4-30.el7_9, xorg-x11-server-Xorg 1.20.4-30.el7_9, +3 more
    fixed: vendor fix RHSA-2025:2861
  • Red Hat Enterprise Linux Server Optional -EXTENSION (v. 6 ELS -EXTENSION) tigervnc-server-applet 1.1.0-25.el6_10, tigervnc-server-module 1.1.0-25.el6_10
    fixed: vendor fix RHSA-2025:3976
  • Red Hat Enterprise Linux Server Optional (v. 7 ELS) xorg-x11-server-Xdmx 1.20.4-30.el7_9, xorg-x11-server-Xvfb 1.20.4-30.el7_9, tigervnc-server-applet 1.8.0-36.el7_9, tigervnc-server-module 1.8.0-36.el7_9, xorg-x11-server-Xnest 1.20.4-30.el7_9, xorg-x11-server-source 1.20.4-30.el7_9, +1 more
    fixed: vendor fix RHSA-2025:2861
  • Red Hat Enterprise Linux 8 xorg-x11-server, xorg-x11-server-Xdmx, xorg-x11-server-Xorg, xorg-x11-server-Xvfb, xorg-x11-server-Xnest, xorg-x11-server-common, +3 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
20 mo ago

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION
  • Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 8.2 Advanced Update Support
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.4 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.6 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 8.8 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.2 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 9.4 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 6

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.