CVSS 3.1
7.8 highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVE-2026-50257
High (7.8). EPSS 0.1% chance of exploitation in the next 30 days.
A use-after-free flaw was found in the X.Org X server and Xwayland in miSyncDestroyFence(). A client that sets up multiple fence triggers can trigger a use-after-free function pointer call. An attacker would connect to the X server to set up a fence and await that fence, then a second X connection destroys the fence, causing the use-after-free. This may be used to crash the server, or for privilege escalation if the X server runs as root.
Severity
- EPSS
- 0.1% chance of exploitation in the next 30 days; higher than 3% of CVEs (scores of 2026-10-31)
- CWE
- CWE-416
- Published
- Modified
- Record from
- the NVD, synced
Affected
- redhat:enterprise_linux
- x.org:x_server
- x.org:xwayland