CVE-2026-50258

7.8 HIGH
Published: June 05, 2026 Modified: June 08, 2026
View on NVD

Description

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. The X server has multiple stack buffers sized XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify or clamp non-canonical key types to XkbMaxShiftLevel. A client can change key types to excessive shift levels and trigger stack overflows. This is caused by an incomplete fix of CVE-2025-26597. This may be used to crash the server, or for privilege escalation if the X server runs as root.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://access.redhat.com/security/cve/CVE-2026-50258
Source: secalert@redhat.com
Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2485383
Source: secalert@redhat.com
Issue Tracking Third Party Advisory
https://lists.x.org/archives/xorg-announce/2026-June/003702.html
Source: secalert@redhat.com
Mailing List Third Party Advisory
https://redhat.atlassian.net/browse/PSIRTSUPT-16950
Source: secalert@redhat.com
Permissions Required

5 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.8 / 10.0
EPSS (Exploit Probability)
0.0%
3th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

x.org redhat