Description
A flaw was found in the XFIXES extension. The XFixesSetClientDisconnectMode handler does not validate the request length, allowing a client to read unintended memory from previous requests.
References7
- access.redhat.com/errata/RHSA-2025:10258
- access.redhat.com/errata/RHSA-2025:9303
- access.redhat.com/errata/RHSA-2025:9304
- access.redhat.com/security/cve/CVE-2025-49177
- bugzilla.redhat.com/show_bug.cgi?id=2369955
- gitlab.freedesktop.org/xorg/xserver/-/commit/ab02fb96b1c701c3bb…
- www.x.org/wiki/Development/Security/
Metrics
- CVSS 3.1
-
6.1
MEDIUM
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L - EPSS — exploit probability
- 0% percentile: 38 · as of 7 November 2026
- CWE
- CWE-200
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.