CVE-2026-50258 - CERT CVE
ID CVE-2026-50258
Sažetak 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.
Reference
CVSS
Base: 7.8
Impact: 5.9
Exploitability:1.8
Pristup
VektorSloženostAutentikacija
LOCAL LOW LOW
Impact
PovjerljivostCjelovitostDostupnost
HIGH HIGH HIGH
CVSS vektor CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Zadnje važnije ažuriranje 08-06-2026 - 16:46
Objavljeno 05-06-2026 - 12:16