🛡️ CVE-2026-50259 — enterprise-linux

🟠 CVSS 7.8 — High ✅ No Known Exploit CWE-121 NVD
7.8
CVSS Score
0 Low4 Medium7 High9 Critical10

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

access.redhat.com
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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

Severity HIGH
CVSS Score 7.8
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE CWE-121
Public Exploit ✅ No
Source NVD
Published 2026-06-05
Updated 2026-08-11
Modified 2026-08-05

Affected Packages

Software From version Fixed in
enterprise-linux
unknown
x-server 21.1.23
xwayland 24.1.12

References

Issue Tracking, Third Party Advisory https://bugzilla.redhat.com/show_bug.cgi?id=2485384
Issue Tracking, Third Party Advisory https://bugzilla.redhat.com/show_bug.cgi?id=2485384

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