High7.8Red Hat Linux

High [CVE-2026-50258] stack buffer overflow in XKB key types due to unchecked shift levels

This high-severity Red Hat Linux advisory covers CVE-2026-50258 affecting Red Hat Enterprise Linux 10.0 Extended Update Support, Red Hat Enterprise Linux 7 Extended Lifecycle Support, Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support.

CVE-2026-50258 Published Jun 2, 2026

CVE-2026-50258

Affected products & platforms

Red Hat LinuxUnclassified

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Summary

stack buffer overflow in XKB key types due to unchecked shift levels. Red Hat rates this important (CVSS 7.8).

Weakness: CWE-121. Affected package(s): xorg-x11-server, xorg-x11-server-Xwayland, tigervnc.

Resolved in Red Hat advisory RHSA-2026:26562 — update the affected packages (`sudo dnf update`).

Affected products named by the advisory: Red Hat Enterprise Linux 10.0 Extended Update Support; Red Hat Enterprise Linux 7 Extended Lifecycle Support; Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support; Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On; and 8 more.

Affected versions

xorg-x11-server-0:1.20.11-34.el9_8.2
xorg-x11-server-Xwayland-0:21.1.3-20.el8_10.2
tigervnc-0:1.15.0-7.el9_8.2
xorg-x11-server-Xwayland-0:24.1.9-4.el9_8.2
xorg-x11-server-0:1.20.11-28.el8_10.2
tigervnc-0:1.15.0-10.el8_10
xorg-x11-server-Xwayland-0:24.1.9-4.el10_2.2

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Fixed versions

RHSA-2026:26562

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Mitigation checklist

Recommended fix / mitigation

Update the affected package(s) to the fixed version shipped in RHSA-2026:26562 (`sudo dnf update` / `yum update`).

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

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