CVE-2026-34001
This use-after-free vulnerability occurs in the XSYNC fence triggering logic, specifically within the miSyncTriggerFence() function.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.26%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.26% probability · 18th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-825
- Source
- secalert@redhat.com
References
- https://access.redhat.com/errata/RHSA-2026:10739
- https://access.redhat.com/errata/RHSA-2026:11352
- https://access.redhat.com/errata/RHSA-2026:11369
- https://access.redhat.com/errata/RHSA-2026:11388
- https://access.redhat.com/errata/RHSA-2026:11656
- https://access.redhat.com/errata/RHSA-2026:11692
- https://access.redhat.com/errata/RHSA-2026:13414
- https://access.redhat.com/errata/RHSA-2026:19125
- https://access.redhat.com/errata/RHSA-2026:19342
- https://access.redhat.com/errata/RHSA-2026:19343
- https://access.redhat.com/errata/RHSA-2026:19344
- https://access.redhat.com/errata/RHSA-2026:20547
- https://access.redhat.com/errata/RHSA-2026:20555
- https://access.redhat.com/errata/RHSA-2026:20557
- https://access.redhat.com/errata/RHSA-2026:20558
- https://access.redhat.com/errata/RHSA-2026:20560
- https://access.redhat.com/errata/RHSA-2026:20561
- https://access.redhat.com/errata/RHSA-2026:20562
- https://access.redhat.com/errata/RHSA-2026:20563
- https://access.redhat.com/errata/RHSA-2026:20575
- https://access.redhat.com/errata/RHSA-2026:20576
- https://access.redhat.com/errata/RHSA-2026:20590
- https://access.redhat.com/errata/RHSA-2026:21699
- https://access.redhat.com/errata/RHSA-2026:21712
- https://access.redhat.com/errata/RHSA-2026:21715
- https://access.redhat.com/errata/RHSA-2026:21716
- https://access.redhat.com/errata/RHSA-2026:21718
- https://access.redhat.com/errata/RHSA-2026:21741
- https://access.redhat.com/errata/RHSA-2026:21742
- https://access.redhat.com/errata/RHSA-2026:22424
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.