A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256] indexed by key type index. The helper function CheckKeyTypes() writes to this buffer at a client-controlled offset, allowing a stack buffer overflow. This may be used to crash the server, or for privilege escalation if the X server runs as root.
History

Fri, 05 Jun 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Fri, 05 Jun 2026 11:45:00 +0000

Type Values Removed Values Added
Description A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256] indexed by key type index. The helper function CheckKeyTypes() writes to this buffer at a client-controlled offset, allowing a stack buffer overflow. This may be used to crash the server, or for privilege escalation if the X server runs as root.
Title Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in xkb setmap request via mapwidths indexing
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-121
CPEs cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-06-05T10:31:39.152Z

Reserved: 2026-06-04T14:55:24.011Z

Link: CVE-2026-50259

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-06-05T12:16:39.240

Modified: 2026-06-05T12:16:39.240

Link: CVE-2026-50259

cve-icon Redhat

Severity : Important

Publid Date: 2026-06-02T00:00:00Z

Links: CVE-2026-50259 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-06-05T12:30:40Z