HIGHVulnerability
CVE-2026-50258
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.
Properties
- severity
- HIGH
- score
- 7.8
- cve_id
- CVE-2026-50258
- vector
- CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- published_at
- 2026-06-05T12:16:39.070
- last_modified
- 2026-08-05T13:23:30.720
Related Entities (8)
AFFECTS_PRODUCT (6)
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HAS_WEAKNESS (1)
→[Weakness]Stack-based Buffer Overflow
DESCRIBED_BY (1)
→[Source]NVD
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