High severity · published Jul 8, 2026
CVE-2026-56000
xorg-x11-server / xwayland GLX contextTags Use-After-Free in CommonMakeCurrent()
7.8
CVSS
0.3%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 23% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
XO
xorg-x11-server · X.Org
before 21.1.24 · source: vendor
XW
xwayland · X.Org
before 24.1.13 · source: vendor, NVD
XS
X Server · X.org
before 21.2.24 · source: NVD
In the news
VulnerabilityHigh
ZDI-26-405: X.Org Server GLX Extension Use-After-Free Privilege Escalation Vulnerability
This vulnerability allows local attackers to escalate privileges on affected installations of X.Org Server. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The ZDI has assigned a CVSS rating of 7.8. The following CVEs are assigned: CVE-2026-56000.
Jul 15, 2026·Zero Day Initiative
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-56000
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-56000
Patch
https://gitlab.freedesktop.org/xorg/xserver/-/commit/2779affbdb4354e894f490e56f962527d6125043
Mailing List
https://www.openwall.com/lists/oss-security/2026/07/08/2
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