HIGHVulnerability
Verified
Global
NVD HIGH: CVE-2026-50259 — A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland....
·Source: NIST NVD
Updated:
Executive Summary
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.
Analysis
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. CVSS Score: 7.8. Published: 2026-06-05T12:16:39.240.