CVE-2026-33999 HIGH

CVE-2026-33999: Xorg: xwayland: x.org x server: denial of service via integer underflow in xkb compatibility map handling

Vendor Red Hat
Product Red Hat Enterprise Linux 6
Weakness CWE-191
Published April 23, 2026
Last update June 30, 2026
View on NVD All CVEs

CVSS base score

7.8/10
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality High
Integrity High

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 23, 2026 CVE published
June 30, 2026 Record updated