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CVE-2026-50261 Details

Description

A use-after-free flaw was found in the X.Org X server and Xwayland in SyncChangeCounter(). A client that sets up multiple SyncCounters can trigger a use-after-free when destroying those counters via a second client connection while changing those counters. This may be used to crash the server, or for privilege escalation if the X server runs as root.

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: redhat-SADPCVSS-B:7.8 HIGHVector:CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.

URLSource(s)Tag(s)
https://access.redhat.com/errata/RHSA-2026:26562 redhat-SADP
https://access.redhat.com/errata/RHSA-2026:26566 redhat-SADP
https://access.redhat.com/errata/RHSA-2026:26590 redhat-SADP
https://access.redhat.com/errata/RHSA-2026:26610 redhat-SADP
https://access.redhat.com/errata/RHSA-2026:26709 redhat-SADP

see all 64 references

Weakness Enumeration

CWE-IDCWE NameSource
CWE-416Use After Freeredhat-SADP
CWE-416Use After Free[email protected]

Affected Products

ProductVersions
x.org x server
< 21.1.23

CPE

  • cpe:2.3:a:x.org:x_server:*:*:*:*:*:*:*:*

Remediation

  • No remediation found in references.
x.org xwayland
< 24.1.12

CPE

  • cpe:2.3:a:x.org:xwayland:*:*:*:*:*:*:*:*

Remediation

  • No remediation found in references.
redhat enterprise linux
7.0
8.0
9.0
10.0

CPE

  • cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
  • cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
  • cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
  • cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*

Remediation

  • No remediation found in references.

Change History

31 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-50261
NVD Published Date:
Jun 5, 2026
NVD Last Modified:
Aug 5, 2026
Source:
[email protected]
CVE-2026-50261 Details - Not Deferred