Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| X.Org | X Server | < 21.1.23 |
| X.Org | Xwayland | < 24.1.12 |
| Redhat | Enterprise Linux | 7.0 |
Related Weaknesses (CWE)
References
- https://access.redhat.com/errata/RHSA-2026:26562
- https://access.redhat.com/errata/RHSA-2026:26566
- https://access.redhat.com/errata/RHSA-2026:26590
- https://access.redhat.com/errata/RHSA-2026:26610
- https://access.redhat.com/errata/RHSA-2026:26709
- https://access.redhat.com/errata/RHSA-2026:28923
- https://access.redhat.com/errata/RHSA-2026:29844
- https://access.redhat.com/errata/RHSA-2026:36083
- https://access.redhat.com/errata/RHSA-2026:36085
- https://access.redhat.com/errata/RHSA-2026:36086
- https://access.redhat.com/errata/RHSA-2026:36087
- https://access.redhat.com/errata/RHSA-2026:36632
- https://access.redhat.com/errata/RHSA-2026:36633
- https://access.redhat.com/errata/RHSA-2026:36634
- https://access.redhat.com/errata/RHSA-2026:36768
FAQ
What is CVE-2026-50261?
CVE-2026-50261 is a vulnerability with a CVSS score of 7.8 (HIGH). 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...
How severe is CVE-2026-50261?
CVE-2026-50261 has been rated HIGH with a CVSS base score of 7.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-50261?
Check the references section above for vendor advisories and patch information. Affected products include: X.Org X Server, X.Org Xwayland, Redhat Enterprise Linux.