CVE-2026-33999

EUVD-2026-25229
A flaw was found in the X.Org X server. This integer underflow vulnerability, specifically in the XKB compatibility map handling, allows an attacker with local or remote X11 server access to trigger a buffer read overrun. This can lead to memory-safety violations and potentially a denial of service (DoS) or other severe impacts.
Wrap or Wraparound
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
7.8 HIGH
LOCAL
LOW
LOW
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Debian logo
Debian Releases
Debian Product
Codename
xorg-server
bookworm
no-dsa
bookworm (security)
vulnerable
bullseye
postponed
bullseye (security)
vulnerable
forky
vulnerable
sid
2:21.1.22-1
fixed
trixie
no-dsa
trixie (security)
vulnerable
xwayland
bookworm
ignored
forky
2:24.1.10-1
fixed
sid
2:24.1.10-1
fixed
trixie
ignored
Common Weakness Enumeration
References
https://access.redhat.com/security/cve/CVE-2026-33999
https://bugzilla.redhat.com/show_bug.cgi?id=2451106