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CVE-2026-33999

Xorg: xwayland: x.org x server: denial of service via integer underflow in xkb compatibility map handling

Published: Apr 23, 2026Updated: Apr 23, 2026 Sources: CVE List
NVD MITRE
7.8CVSS
HIGH

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.

EPSS Score
N/A
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Workaround Only

CVSS Vector Breakdown

AV:LAC:LPR:LUI:NS:UC:HI:HA:H
Exploitability
AV:LAttack Vector
Local
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High

Weaknesses

CWE-191Integer Underflow (Wrap or Wraparound)

Affected Products

Red Hat Enterprise Linux 10
Red Hat
Red Hat Enterprise Linux 6
Red Hat
Red Hat Enterprise Linux 7
Red Hat
Red Hat Enterprise Linux 8
Red Hat
Red Hat Enterprise Linux 9
Red Hat

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Workaround Available

MITRE ATT&CK

1 technique
Initial Access
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References

https://access.redhat.com/security/cve/CVE-2026-33999
access.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2451106
bugzilla.redhat.com

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