CVE-2026-50258EPSS p11.9%
CVE-2026-50258CVE-2026-50258
x.org / x_server
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.
Scoring
| CVSS | 7.8 () |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 0.22% probability of exploitation · percentile 11.9% · 2026-06-19T12:03:05Z |
| Last modified | 2026-06-08 |
Related by meaning· 6
Nearest entities by semantic similarity across the cs-graph corpus.