CVE-2025-26601

HIGH
MEDIUM Priority: 0.03 BB Relevance: 41/100
Published: 2025-02-25 Modified: 2026-11-04 First seen: 2026-11-04 Status: active

Attack Surface

Low Complexity No Interaction Conf. Impact Integ. Impact

CVSS Vector Breakdown

AV: Local
AC: Low
PR: Low
UI: None
S: Unchanged
C: High
I: High
A: High

Description

A use-after-free flaw was found in X.Org and Xwayland. When changing an alarm, the values of the change mask are evaluated one after the other, changing the trigger values as requested, and eventually, SyncInitTrigger() is called. If one of the changes triggers an error, the function will return early, not adding the new sync object, possibly causing a use-after-free when the alarm eventually triggers.

Weakness Classification (1)

Affected Software (8)

VendorProductVersion
&mdash; &mdash; 0 < 21.1.16
&mdash; &mdash; 22.0.0 < 24.1.6
redhat enterprise_linux 7.0
redhat enterprise_linux 8.0
redhat enterprise_linux 9.0
tigervnc tigervnc -
x.org x_server < 21.1.16
x.org xwayland < 24.1.6

References & Advisories (19)

https://access.redhat.com/errata/RHSA-2025:2500
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:2502
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:2861
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:2862
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:2865
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:2866
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:2873
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:2874
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:2875
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:2879
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:2880
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:3976
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:7163
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:7165
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2025:7458
vendor-advisory x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2345251
issue-tracking x_refsource_REDHAT

Bug Bounty Relevance

41 / 100
✓ Low complexity
✓ No user interaction

CVSS Score

7.8 / 10.0 v3.1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploitation Probability

0.39%
Raw Score 0.003930
Percentile 33.8%
Date 2026-11-09

EPSS Trend

2026-11-09
0.00393
2026-11-08
0.00393
2026-11-07
0.00393
2026-11-06
0.00393
2026-11-05
0.00393
2026-11-04
0.00393

Intelligence Sources

mitre ref →
nvd ref →