CVE-2026-50258 — HIGH (7.8)

Q: How severe is CVE-2026-50258?

CVE-2026-50258 has been rated HIGH with a CVSS base score of 7.8/10. Review the CVSS metrics above for detailed severity breakdown.

Q: Is there a patch for CVE-2026-50258?

Check the references section above for vendor advisories and patch information. Affected products include: X.Org X Server, X.Org Xwayland, Redhat Enterprise Linux.

Vulnerability 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.

CVSS Score

7.8

HIGH

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

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

HIGH

Affected Products

Vendor	Product	Versions
X.Org	X Server	< 21.1.23
X.Org	Xwayland	< 24.1.12
Redhat	Enterprise Linux	7.0

Related Weaknesses (CWE)

CWE-121

References

FAQ

What is CVE-2026-50258?

CVE-2026-50258 is a vulnerability with a CVSS score of 7.8 (HIGH). 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...

How severe is CVE-2026-50258?

CVE-2026-50258 has been rated HIGH with a CVSS base score of 7.8/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-50258?

Check the references section above for vendor advisories and patch information. Affected products include: X.Org X Server, X.Org Xwayland, Redhat Enterprise Linux.