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.
References
| Link | Resource |
|---|---|
| https://access.redhat.com/security/cve/CVE-2026-50258 | Third Party Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2485383 | Issue Tracking Third Party Advisory |
| https://gitlab.freedesktop.org/xorg/xserver/-/commit/543e108516428fc8c3bea91d6563ad266f9a801e | Patch |
| https://lists.x.org/archives/xorg-announce/2026-June/003702.html | Mailing List Third Party Advisory |
| https://redhat.atlassian.net/browse/PSIRTSUPT-16950 | Permissions Required |
Configurations
Configuration 1 (hide)
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History
08 Jun 2026, 16:46
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://access.redhat.com/security/cve/CVE-2026-50258 - Third Party Advisory | |
| References | () https://bugzilla.redhat.com/show_bug.cgi?id=2485383 - Issue Tracking, Third Party Advisory | |
| References | () https://gitlab.freedesktop.org/xorg/xserver/-/commit/543e108516428fc8c3bea91d6563ad266f9a801e - Patch | |
| References | () https://lists.x.org/archives/xorg-announce/2026-June/003702.html - Mailing List, Third Party Advisory | |
| References | () https://redhat.atlassian.net/browse/PSIRTSUPT-16950 - Permissions Required | |
| CPE | cpe:2.3:a:x.org:xwayland:*:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* cpe:2.3:a:x.org:x_server:*:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* |
|
| First Time |
Redhat enterprise Linux
Redhat X.org X.org xwayland X.org x Server |
05 Jun 2026, 12:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-06-05 12:16
Updated : 2026-06-08 16:46
NVD link : CVE-2026-50258
Mitre link : CVE-2026-50258
CVE.ORG link : CVE-2026-50258
JSON object : View
Products Affected
x.org
- x_server
- xwayland
redhat
- enterprise_linux
CWE
CWE-121
Stack-based Buffer Overflow