Description
A flaw was found in the X.Org X server. This use-after-free vulnerability occurs in the XSYNC fence triggering logic, specifically within the miSyncTriggerFence() function. An attacker with access to the X11 server can exploit this without user interaction, leading to a server crash and potentially enabling memory corruption. This could result in a denial of service or further compromise of the system.
References10
- access.redhat.com/errata/RHSA-2026:10739
- access.redhat.com/errata/RHSA-2026:11352
- access.redhat.com/errata/RHSA-2026:11369
- access.redhat.com/errata/RHSA-2026:11388
- access.redhat.com/errata/RHSA-2026:11656
- access.redhat.com/errata/RHSA-2026:11692
- access.redhat.com/errata/RHSA-2026:13414
- access.redhat.com/errata/RHSA-2026:19125
- access.redhat.com/errata/RHSA-2026:19342
- access.redhat.com/errata/RHSA-2026:19343
Metrics
- CVSS 3.1
-
7.8
HIGH
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 18 · as of 13 November 2026
- CWE
- CWE-825
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.