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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.

PUBLISHED Reserved 2026-03-25 | Published 2026-04-23 | Updated 2026-04-29 | Assigner redhat




HIGH: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Problem types

Expired Pointer Dereference

Product status

Default status
affected

0:24.1.5-6.el10_1 (rpm) before *
unaffected

Default status
affected

0:1.20.11-28.el8_10 (rpm) before *
unaffected

Default status
affected

0:1.15.0-6.el9_7.1 (rpm) before *
unaffected

Default status
affected

0:23.2.7-6.el9_7 (rpm) before *
unaffected

Default status
affected

0:1.20.11-33.el9_7 (rpm) before *
unaffected

Default status
affected

Default status
unknown

Default status
affected

Default status
affected

Default status
affected

Default status
affected

Timeline

2026-03-25:Reported to Red Hat.
2026-04-23:Made public.

Credits

Red Hat would like to thank Jan-Niklas Sohn (TrendAI Zero Day Initiative) for reporting this issue.

References

access.redhat.com/errata/RHSA-2026:10739 (RHSA-2026:10739) vendor-advisory

access.redhat.com/errata/RHSA-2026:11352 (RHSA-2026:11352) vendor-advisory

access.redhat.com/errata/RHSA-2026:11369 (RHSA-2026:11369) vendor-advisory

access.redhat.com/errata/RHSA-2026:11388 (RHSA-2026:11388) vendor-advisory

access.redhat.com/errata/RHSA-2026:11692 (RHSA-2026:11692) vendor-advisory

access.redhat.com/security/cve/CVE-2026-34001 vdb-entry

bugzilla.redhat.com/show_bug.cgi?id=2451109 (RHBZ#2451109) issue-tracking

cve.org (CVE-2026-34001)

nvd.nist.gov (CVE-2026-34001)

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