CVE-2025-26601: xserver · Use After Free
Affects xserverSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 5 Nov 2026, 00:01 UTC
Thin evidence
One scorer or none| CNA (redhat) | CVSS 3.1 | 7.8 |
|---|
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Feb 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| xserver | Affected
| Fixed in– |
AI-suggested
Red Hat has released official security updates that fix this vulnerability. Users of affected Red Hat Enterprise Linux 9 versions should apply the provided patches promptly. The vendor advisory (RHSA-2025:2500) contains detailed instructions for updating affected packages. No additional mitigation steps are required beyond applying the official fix.
Description
CVE-2025-26601 is a use-after-free vulnerability in X.Org and Xwayland components of the xserver. The flaw occurs when changing an alarm's trigger values; if an error arises during the change mask evaluation, the function returns early without adding a new sync object, potentially causing a use-after-free when the alarm triggers. This vulnerability has a high severity with a CVSS score of 7.8. Red Hat has issued security updates addressing this and related vulnerabilities in xserver and xwayland.
References
- access.redhat.com/errata/RHSA-2025:2500 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:2502 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:2861 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:2862 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:2865 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:2866 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:2873 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:2874 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:2875 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:2879 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:2880 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:3976 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:7163 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:7165 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:7458 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2025-26601 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2345251 (opens in a new tab)
- security.netapp.com/advisory/ntap-20250516-0004/ (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/02/msg00036.html (opens in a new tab)