CVE-2026-50261
Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free in syncchangecounter()
02 Description
Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free in syncchangecounter()
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
- Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
- EPSS probability
- 0.15% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 4.4% of scored records. A rank, not a probability.
- NVD base score
- 7.8 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVD analysis status
- Modified. NVD last modified this record on 2026-08-05.
- Red Hat severity
- Important. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-06-05 10:36Z4 MO AGO
- Last updated
- 2026-09-28 11:46Z1 MO AGO
- Reserved
- 2026-06-04
- Assigning CNA
- redhat
- Record state
- PUBLISHED
- Severity
- High (CVSS 7.8)
- CNA CVSS vector
- CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weaknesses
- CWE-416Use After FreeVariant
- Data version
- 5.2
- Document digest
- ac04226a0670df9e0ffbedba43aec9e3adb02a3ce0e6ca3e236ca51b6df1369d
05 Affected products
06 References
- access.redhat.comRHSA-2026:26562https://access.redhat.com/errata/RHSA-2026:26562
- access.redhat.comRHSA-2026:26566https://access.redhat.com/errata/RHSA-2026:26566
- access.redhat.comRHSA-2026:26590https://access.redhat.com/errata/RHSA-2026:26590
- access.redhat.comRHSA-2026:26610https://access.redhat.com/errata/RHSA-2026:26610
- access.redhat.comRHSA-2026:26709https://access.redhat.com/errata/RHSA-2026:26709
- access.redhat.comRHSA-2026:28923https://access.redhat.com/errata/RHSA-2026:28923
- access.redhat.comRHSA-2026:29844https://access.redhat.com/errata/RHSA-2026:29844
- access.redhat.comRHSA-2026:36083https://access.redhat.com/errata/RHSA-2026:36083
- access.redhat.comRHSA-2026:36085https://access.redhat.com/errata/RHSA-2026:36085
- access.redhat.comRHSA-2026:36086https://access.redhat.com/errata/RHSA-2026:36086
- access.redhat.comRHSA-2026:36087https://access.redhat.com/errata/RHSA-2026:36087
- access.redhat.comRHSA-2026:36632https://access.redhat.com/errata/RHSA-2026:36632
- access.redhat.comRHSA-2026:36633https://access.redhat.com/errata/RHSA-2026:36633
- access.redhat.comRHSA-2026:36634https://access.redhat.com/errata/RHSA-2026:36634
- access.redhat.comRHSA-2026:36768https://access.redhat.com/errata/RHSA-2026:36768
- access.redhat.comRHSA-2026:36791https://access.redhat.com/errata/RHSA-2026:36791
- access.redhat.comRHSA-2026:36792https://access.redhat.com/errata/RHSA-2026:36792
- access.redhat.comRHSA-2026:36798https://access.redhat.com/errata/RHSA-2026:36798
- access.redhat.comRHSA-2026:38502https://access.redhat.com/errata/RHSA-2026:38502
- access.redhat.comRHSA-2026:38810https://access.redhat.com/errata/RHSA-2026:38810
- access.redhat.comRHSA-2026:46377https://access.redhat.com/errata/RHSA-2026:46377
- access.redhat.comRHSA-2026:46382https://access.redhat.com/errata/RHSA-2026:46382
- access.redhat.comRHSA-2026:46385https://access.redhat.com/errata/RHSA-2026:46385
- access.redhat.comRHSA-2026:46392https://access.redhat.com/errata/RHSA-2026:46392
- access.redhat.comRHSA-2026:46456https://access.redhat.com/errata/RHSA-2026:46456
- access.redhat.comRHSA-2026:46460https://access.redhat.com/errata/RHSA-2026:46460
- access.redhat.comRHSA-2026:46473https://access.redhat.com/errata/RHSA-2026:46473
- access.redhat.comRHSA-2026:49519https://access.redhat.com/errata/RHSA-2026:49519
- access.redhat.comhttps://access.redhat.com/security/cve/CVE-2026-50261
- bugzilla.redhat.comRHBZ#2485386https://bugzilla.redhat.com/show_bug.cgi?id=2485386
- gitlab.freedesktop.orghttps://gitlab.freedesktop.org/xorg/xserver/-/commit/bdd7bf57af208b1ddf57d4683d67104443b44812
- lists.x.orghttps://lists.x.org/archives/xorg-announce/2026-June/003702.html
- redhat.atlassian.nethttps://redhat.atlassian.net/browse/PSIRTSUPT-16950
- security.access.redhat.comhttps://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-50261.json
07 Fixed in
AlmaLinux 8
- tigervnc Fixed in 1.15.0-10.el8_10
- tigervnc-icons Fixed in 1.15.0-10.el8_10
- tigervnc-license Fixed in 1.15.0-10.el8_10
- tigervnc-selinux Fixed in 1.15.0-10.el8_10
- tigervnc-server Fixed in 1.15.0-10.el8_10
- tigervnc-server-minimal Fixed in 1.15.0-10.el8_10
- tigervnc-server-module Fixed in 1.15.0-10.el8_10
- xorg-x11-server-Xdmx Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-Xephyr Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-Xnest Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-Xorg Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-Xvfb Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-Xwayland Fixed in 21.1.3-20.el8_10.2
- xorg-x11-server-common Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-devel Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-source Fixed in 1.20.11-28.el8_10.2
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
AlmaLinux 9
- tigervnc Fixed in 1.15.0-7.el9_8.2
- tigervnc-icons Fixed in 1.15.0-7.el9_8.2
- tigervnc-license Fixed in 1.15.0-7.el9_8.2
- tigervnc-selinux Fixed in 1.15.0-7.el9_8.2
- tigervnc-server Fixed in 1.15.0-7.el9_8.2
- tigervnc-server-minimal Fixed in 1.15.0-7.el9_8.2
- tigervnc-server-module Fixed in 1.15.0-7.el9_8.2
- xorg-x11-server-Xdmx Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-Xephyr Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-Xnest Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-Xorg Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-Xvfb Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-Xwayland Fixed in 24.1.9-4.el9_8.2
- xorg-x11-server-Xwayland-devel Fixed in 24.1.9-4.el9_8.2
- xorg-x11-server-common Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-devel Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-source Fixed in 1.20.11-34.el9_8.2
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
AlmaLinux 10
- xorg-x11-server-Xwayland Fixed in 24.1.9-4.el10_2.2
- xorg-x11-server-Xwayland-devel Fixed in 24.1.9-4.el10_2.2
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 8
- tigervnc Fixed in 1.15.0-10.el8_10
- tigervnc-icons Fixed in 1.15.0-10.el8_10
- tigervnc-license Fixed in 1.15.0-10.el8_10
- tigervnc-selinux Fixed in 1.15.0-10.el8_10
- tigervnc-server Fixed in 1.15.0-10.el8_10
- tigervnc-server-minimal Fixed in 1.15.0-10.el8_10
- tigervnc-server-module Fixed in 1.15.0-10.el8_10
- xorg-x11-server-Xdmx Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-Xephyr Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-Xnest Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-Xorg Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-Xvfb Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-Xwayland Fixed in 21.1.3-20.el8_10.2
- xorg-x11-server-common Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-devel Fixed in 1.20.11-28.el8_10.2
- xorg-x11-server-source Fixed in 1.20.11-28.el8_10.2
Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 9
- tigervnc Fixed in 1.15.0-7.el9_8.2
- tigervnc-icons Fixed in 1.15.0-7.el9_8.2
- tigervnc-license Fixed in 1.15.0-7.el9_8.2
- tigervnc-selinux Fixed in 1.15.0-7.el9_8.2
- tigervnc-server Fixed in 1.15.0-7.el9_8.2
- tigervnc-server-minimal Fixed in 1.15.0-7.el9_8.2
- tigervnc-server-module Fixed in 1.15.0-7.el9_8.2
- xorg-x11-server-Xdmx Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-Xephyr Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-Xnest Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-Xorg Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-Xvfb Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-Xwayland Fixed in 24.1.9-4.el9_8.2
- xorg-x11-server-Xwayland-devel Fixed in 24.1.9-4.el9_8.2
- xorg-x11-server-common Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-devel Fixed in 1.20.11-34.el9_8.2
- xorg-x11-server-source Fixed in 1.20.11-34.el9_8.2
Derived from AlmaLinux 9. Partial coverage: only packages taken from AlmaLinux 9 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 10
- xorg-x11-server-Xwayland Fixed in 24.1.9-4.el10_2.2
- xorg-x11-server-Xwayland-devel Fixed in 24.1.9-4.el10_2.2
Derived from AlmaLinux 10. Partial coverage: only packages taken from AlmaLinux 10 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Debian 12
- xorg-server Fixed in 2:21.1.7-3+deb12u13
- xwayland No fix yet
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- xorg-server Fixed in 2:21.1.16-1.3+deb13u3
- xwayland No fix yet
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- xorg-server Fixed in 2:21.1.23-1
- xwayland Fixed in 2:24.1.12-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 22.04 LTS
- xorg-server No fix yet
- xwayland No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 24.04 LTS
- xorg-server No fix yet
- xwayland No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 25.10
- xorg-server No fix yet
- xwayland No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 26.04 LTS
- xorg-server No fix yet
- xwayland No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 26.10
- xorg-server No fix yet
- xwayland No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 14.04 LTS
- xorg-server No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 16.04 LTS
- xorg-server No fix yet
- xorg-server-hwe-16.04 No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 18.04 LTS
- xorg-server No fix yet
- xorg-server-hwe-18.04 No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 20.04 LTS
- xorg-server No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.