X.Org X Server and X Wayland: Double free vulnerability in XKB SetGeometry (CVE-2026-88812)
A double-free vulnerability in the XKB SetGeometry implementation in X.Org X Server and X Wayland allows local clients to cause a denial of service or potential arbitrary code execution.
CVE search metadata
CVE search record: CVE-2026-88812. Severity: high. CVSS: 7.8. KEV: no. Product: X Server (< 21.1.25), X Wayland (< 24.1.14). Brief: X.Org X Server and X Wayland: Double free vulnerability in XKB SetGeometry (CVE-2026-88812). Brief link: https://feed.craftedsignal.io/briefs/2026-10-xorg-xkb-double-free/
Triage facts
Revision 1- Applicability
- X Server (< 21.1.25), X Wayland (< 24.1.14)
- Evidence
- Unknown
- Severity
- High
- Action
- Elevated
- Sources
- 1 public source
- Freshness
- Revision 1Oct 28, 02:16 UTC
- Vulnerabilities
- 1 CVE
- Source quality
- A1Roughly even chance
CVE-2026-88812 is a memory corruption vulnerability involving a double-free condition in the XKB (X Keyboard Extension) SetGeometry implementation. This flaw affects versions of X.Org X Server prior to 21.1.25 and X Wayland prior to 24.1.14. An attacker with the ability to connect as a client to the X server can exploit this vulnerability to trigger a crash, resulting in a denial of service, or potentially gain arbitrary code execution within the context of the X server process.
Impact
Successful exploitation may lead to a crash of the X server process (Denial of Service) or arbitrary code execution under the privileges of the X server instance.
Recommendation
- Upgrade X.Org X Server to version 21.1.25 or later.
- Upgrade X Wayland to version 24.1.14 or later.
- Review system audit logs for repeated X server process restarts, which may indicate exploit attempts.
Threat Hunt
Monitor X server crash logs and process restart frequency
Data: systemd journal or syslog entries for xorg/xwayland
Mitigations
Upgrade X.Org X Server to 21.1.25 and X Wayland to 24.1.14
CVE-2026-88812