GHSA-74fp-pmv2-rh3fHighCVSS 7.8
A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. The X server has...
🔗 CVE IDs covered (1)
📋 Description
A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. The X server has multiple stack buffers sized XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify or clamp non-canonical key types to XkbMaxShiftLevel. A client can change key types to excessive shift levels and trigger stack overflows. This is caused by an incomplete fix of CVE-2025-26597. This may be used to crash the server, or for privilege escalation if the X server runs as root.
🔗 References (7)
- https://nvd.nist.gov/vuln/detail/CVE-2026-50258
- https://access.redhat.com/security/cve/CVE-2026-50258
- https://bugzilla.redhat.com/show_bug.cgi?id=2485383
- https://gitlab.freedesktop.org/xorg/xserver/-/commit/543e108516428fc8c3bea91d6563ad266f9a801e
- https://lists.x.org/archives/xorg-announce/2026-June/003702.html
- https://redhat.atlassian.net/browse/PSIRTSUPT-16950
- https://github.com/advisories/GHSA-74fp-pmv2-rh3f