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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: Jun 30, 2026 Sources: CVE List NVD BDUCWE-191
7.8HIGH
NVD MITRE
EPSS Score
0.4%
Top 70.1%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

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.

No summary for this CVE yet.

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
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Weaknesses

CWE-191

Affected Products

Red Hat Inc.
commercial·USaka Red Hat
Red Hat Enterprise Linux 10On-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 10.0 Extended Update SupportOn-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSIONOn-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 7 Extended Lifecycle SupportOn-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportOn-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-OnOn-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update SupportOn-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-OnOn-premOS
Operating Systems / linux-distro
АО «ИВК»
commercial·RUaka ivk
АЛЬТ СП 10On-premOS
Operating Systems / linux-distro
X.Org Foundation
oss-project·USaka libx11, xorg-server, xlib
X.Org Server
Operating Systems / unix-bsd
Сообщество свободного программного обеспечения
oss-projectaka fsf
XWaylandOn-prem
Operating Systems / linux-distro
and 12 more affected products View all →

Exploitability

Official Patch Available
Workaround Available
Scannable·OpenVAS
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Initial Access
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References

https://access.redhat.com/errata/RHSA-2026:10739
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:11352
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:11369
access.redhat.com
and 41 more references View all →
News mentions
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