🛡️ CVE-2026-50259 — enterprise-linux
Description
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.
How this vulnerability can be exploited
This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.
Weakness class
CVE-2026-50259 is classified as CWE-121: Stack-based Buffer Overflow. An oversized write to a stack buffer overwrites saved state such as return addresses, which can redirect execution.
Affected software
CVE-2026-50259 is recorded against 4 packages.
- enterprise-linux
- unknown
- x-server (fixed in 21.1.23)
- xwayland (fixed in 24.1.12)
Timeline and source
Published on 5 June 2026 and last revised on 5 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.
References
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CVE-2026-50259 on other distributions
Each distribution ships its own build and its own fixed version. Pick the one you run:
Details
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| enterprise-linux | — | — |
| unknown | — | — |
| x-server | — | 21.1.23 |
| xwayland | — | 24.1.12 |
References
Similar Threats
- Medium CVE-2022-0851
- High CVE-2022-0358
- Medium CVE-2022-0480
- Medium CVE-2022-0485
- Medium CVE-2022-0852
More CVE 2026 advisories
Browse all of CVE 2026 in the advisory index.
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