CVE-2026-33999
Xorg: xwayland: x.org x server: denial of service via integer underflow in xkb compatibility map handling
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
Exploitability
AV:LAttack VectorLocal
AC:LAttack ComplexityLow
PR:LPrivileges RequiredLow
UI:NUser InteractionNone
Scope
S:UScopeUnchanged
Impact
C:HConfidentialityHigh
I:HIntegrityHigh
A:HAvailabilityHigh
Weaknesses
Affected Products
Red Hat Inc.
commercial·USaka Red Hat
АО «ИВК»
commercial·RUaka ivk
X.Org Foundation
oss-project·USaka libx11, xlib, xorg-server
Сообщество свободного программного обеспечения
oss-projectaka fsf
and 12 more affected products View all →
Exploitability
Official Patch Available
Workaround Available
Attack Graph
Products CVE Techniques Tactics
Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.
MITRE ATT&CK
1 technique Initial Access
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
https://lists.x.org/archives/xorg-announce/2026-April/003678.html
lists.x.org
and 41 more references View all →
Unlock Complete Vulnerability Intelligence
Get the full picture for CVE-2026-33999 and every CVE in our database. Create a free account — no credit card required.
Create Free AccountPlain-language analysis
Impact assessment and exploitation scenario in plain English
Attack graph visualization
Interactive attack path and kill chain mapping
Exploit details & PoC links
ExploitDB, Metasploit, GitHub PoCs with direct links
Nuclei scanner templates
Ready-to-use vulnerability scanner templates
Full remediation guide
Patch instructions, workarounds, and compliance impact
Interactive AI chat
Ask questions about this vulnerability in natural language
Related vulnerabilities
Semantically similar CVEs and attack patterns
REST API & MCP access
Integrate vulnerability data into your workflows