CVE-2026-56000 json
xorg-x11-server / xwayland GLX contextTags Use-After-Free in CommonMakeCurrent()
published 2026-07-08 4 mo ago modified 2026-07-09 4 mo ago also EUVD-2026-42202
- cvss
- 7.8
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 23%
- public exploits
- 0
- none known
Summary
Local attackers with a X connection able to provide GLX commit to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a Heap Use After Free, due to CommonMakeCurrent() pointing into potentially reallocated memory.
Patch / fix
- X.Org xorg-x11-server 21.1.24
- X.Org xwayland 24.1.13
- xwayland Debian 14 2:24.1.13-1
- xorg-server Debian 13 2:21.1.16-1.3+deb13u4
- xorg-server Debian 14 2:21.1.24-1
debian advisories DEBIAN-CVE-2026-56000
- xorg-x11-server-Xwayland RHEL 9 24.1.9-4.el9_8.3
- xorg-x11-server-Xwayland RHEL 10.2 24.1.9-4.el10_2.3
- xorg-x11-server-Xwayland RHEL 9.4 E4S 22.1.9-8.el9_4.3
- xorg-x11-server-Xwayland RHEL 9.6 EUS 23.2.7-6.el9_6.3
- xorg-x11-server-Xwayland enterprise linux eus 10.0 24.1.5-6.el10_0.2
red hat advisories RHSA-2026:52398RHSA-2026:50718RHSA-2026:50100RHSA-2026:38490RHSA-2026:38489
- xwayland SLES for SAP applications 16.0, SLES 16.0 24.1.6-160000.6.1
- xorg-x11-server SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 21.1.4-150500.7.52.1
- xorg-x11-server SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 1.20.3-150400.38.74.1
- xorg-x11-server SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 21.1.15-150700.5.22.1
- xwayland SLE Workstation Extension 15 SP7 24.1.5-150700.3.22.1
- xorg-x11-server SLES for SAP 15 SP6, SLES 15 SP6-LTSS 21.1.11-150600.5.31.1
suse advisories SUSE-SU-2026:22617-1SUSE-SU-2026:2791-1SUSE-SU-2026:2789-1SUSE-SU-2026:2788-1SUSE-SU-2026:2787-1SUSE-SU-2026:2786-1
- xwayland openSUSE Leap 16.0 24.1.6-160000.6.1
- xorg-x11-server openSUSE Tumbleweed 21.1.21-8.1
- xorg-x11-server openSUSE Leap 16.0 21.1.15-160000.6.1
- xwayland openSUSE Tumbleweed 24.1.12-1.1
opensuse advisories openSUSE-SU-2026:21283-1openSUSE-SU-2026:11244-1openSUSE-SU-2026:21273-1openSUSE-SU-2026:11227-1
- xorg-x11-server-Xwayland AlmaLinux 10 24.1.9-4.el10_2.3
- xorg-x11-server-Xwayland AlmaLinux 9 24.1.9-4.el9_8.3
almalinux advisories ALSA-2026:38489ALSA-2026:38490
- xorg-x11-server-Xwayland Rocky Linux 10 24.1.9-4.el10_2.3
- xorg-x11-server-Xwayland Rocky Linux 9 24.1.9-4.el9_8.3
rocky linux advisories RLSA-2026:38489RLSA-2026:38490
- xwayland Alpine 3.24 24.1.13-r0
- xorg-server Alpine 3.24 21.1.24-r0
alpine advisories ALPINE-CVE-2026-56000
Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0
- xorg-x11-server-Xwayland Azure Linux 3.0 24.1.13-1
azure linux advisories AZL-92265
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-2026-56000 updated cvss 6.5
X.org: xorg-x11-server: GLX contextTags Use-After-Free in CommonMakeCurrent()
-
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 Red Hat Enterprise Linux 9 xorg-x11-server, xorg-x11-server-Xdmx, xorg-x11-server-Xorg, xorg-x11-server-Xvfb, xorg-x11-server-Xnest, xorg-x11-server-common, +2 moreaffected: no fix available
-
Red Hat CodeReady Linux Builder EUS (v.9.6) xorg-x11-server-Xwayland 23.2.7-6.el9_6.3fixed: vendor fix RHSA-2026:50718
-
Red Hat Enterprise Linux AppStream (v. 9) xorg-x11-server-Xwayland 24.1.9-4.el9_8.3fixed: vendor fix RHSA-2026:38490
-
Red Hat Enterprise Linux AppStream (v. 10) xorg-x11-server-Xwayland 24.1.9-4.el10_2.3fixed: vendor fix RHSA-2026:38489
-
Red Hat Enterprise Linux AppStream E4S (v.9.4) xorg-x11-server-Xwayland 22.1.9-8.el9_4.3fixed: vendor fix RHSA-2026:52398
-
Red Hat Enterprise Linux AppStream EUS (v. 10.0) xorg-x11-server-Xwayland 24.1.5-6.el10_0.2fixed: vendor fix RHSA-2026:50100
-
Red Hat Enterprise Linux AppStream EUS (v.9.6) xorg-x11-server-Xwayland 23.2.7-6.el9_6.3fixed: vendor fix RHSA-2026:50718
-
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) xorg-x11-server-Xwayland 24.1.9-4.el9_8.3fixed: vendor fix RHSA-2026:38490
show 3 moreshow fewer
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Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) xorg-x11-server-Xwayland-devel 24.1.9-4.el10_2.3, xorg-x11-server-Xwayland-debuginfo 24.1.9-4.el10_2.3, xorg-x11-server-Xwayland-debugsource 24.1.9-4.el10_2.3fixed: vendor fix RHSA-2026:38489
-
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) xorg-x11-server-Xwayland-devel 24.1.5-6.el10_0.2, xorg-x11-server-Xwayland-debuginfo 24.1.5-6.el10_0.2, xorg-x11-server-Xwayland-debugsource 24.1.5-6.el10_0.2fixed: vendor fix RHSA-2026:50100
-
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 Red Hat Enterprise Linux 7 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 Red Hat Enterprise Linux 8 xorg-x11-server-Xwaylandnot 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
- 4 mo ago
Exploit prediction
0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 9.0 | CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H |
| CNA | 4.0 | 9.0 | CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| 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
- X.Org xorg-x11-server
- X.Org xwayland
Classification
- Weakness
-
- CWE-416 Use After Free
References
-
gitlab.freedesktop.org
/xorg/xserver/-/commit/2779affbdb4354e894f490e56f962527d6125043
patch
-
openwall.com
/lists/oss-security/2026/07/08/2
vendor-advisory, mailing-list, patch, third-party-advisory
Sources
- CVE List CVE-2026-56000
- NVD CVE-2026-56000
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.