CVE-2026-33999

HIGH

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

Title source: cna

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.

References (8)

[Vendor Advisory] https://access.redhat.com/errata/RHSA-2026:11352

[Vendor Advisory] https://access.redhat.com/errata/RHSA-2026:11369

[Vendor Advisory] https://access.redhat.com/errata/RHSA-2026:11388

[Vendor Advisory] https://access.redhat.com/errata/RHSA-2026:11656

[Vendor Advisory] https://access.redhat.com/errata/RHSA-2026:11692

[Vdb Entry, X_Refsource_Redhat] https://access.redhat.com/security/cve/CVE-2026-33999

[Issue Tracking, X_Refsource_Redhat] https://bugzilla.redhat.com/show_bug.cgi?id=2451106

[Vendor Advisory] https://access.redhat.com/errata/RHSA-2026:10739

Scores

CVSS v3 7.8

EPSS 0.0001

EPSS Percentile 1.8%

Attack Vector LOCAL

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment

Exploitation none

Automatable no

Technical Impact total

Details

CWE

CWE-191

Status published

Products (11)

Red Hat/Red Hat Enterprise Linux 10

Red Hat/Red Hat Enterprise Linux 10 0:24.1.5-6.el10_1

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 8 0:1.20.11-28.el8_10

Red Hat/Red Hat Enterprise Linux 8 0:21.1.3-20.el8_10

Red Hat/Red Hat Enterprise Linux 9

Red Hat/Red Hat Enterprise Linux 9 0:1.15.0-6.el9_7.1

Red Hat/Red Hat Enterprise Linux 9 0:1.20.11-33.el9_7

... and 1 more

Published Apr 23, 2026

Tracked Since Apr 23, 2026