CVE-2026-50261

CVE-2026-50261

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 changin…

Vulnerability class: Use-After-Free

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-50261?
CVE-2026-50261 is a high-severity vulnerability, classified under Use After Free. CVSS score: 7.8/10. Published 2026-06-05.
How severe is CVE-2026-50261?
High severity. CVSS v3 base score is 7.8 out of 10.