Is CVE-2026-34003 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-34003 being exploited in the wild.

How severe is CVE-2026-34003?

High severity, with a CVSS score of 7.8, published 23 April 2026.

Which products and versions are affected?

X.Org Foundation X Server All versions prior to April 2026 patches.

Is there a fix for CVE-2026-34003?

A patch was published on 2026-04-27: Red Hat released security updates for RHEL 9 (RHSA-2026:10739) Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-34003 attacked?

It is attacked with local access, in an operating system.

Am I affected by CVE-2026-34003?

Check whether you run Tigervnc, X.Org Foundation X Server or X.Org Foundation Xwayland at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-34003: X.Org X server out-of-bounds memory access in XKB request validation

CVE-2026-34003 · Severity: high · CVSS 7.8 · Published 2026-04-23

A security vulnerability has been identified in the X.Org X server, a fundamental component used to manage graphical displays and user input on Linux systems. A local user could exploit this flaw to crash the system or potentially access sensitive information stored in memory. This could lead to a disruption of services or unauthorized data exposure on affected workstations and servers.

Technologies: Tigervnc, X.Org Foundation X Server, X.Org Foundation Xwayland. Vendors: Tigervnc, X.Org Foundation.

Quick answers

Is CVE-2026-34003 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-34003 being exploited in the wild.
How severe is CVE-2026-34003?: High severity, with a CVSS score of 7.8, published 23 April 2026.
Which products and versions are affected?: X.Org Foundation X Server All versions prior to April 2026 patches.
Is there a fix for CVE-2026-34003?: A patch was published on 2026-04-27: Red Hat released security updates for RHEL 9 (RHSA-2026:10739) Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-34003 attacked?: It is attacked with local access, in an operating system.
Am I affected by CVE-2026-34003?: Check whether you run Tigervnc, X.Org Foundation X Server or X.Org Foundation Xwayland at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An out-of-bounds (OOB) read vulnerability (CWE-125) exists in the X.Org X server's XKB (X Keyboard Extension) key types request validation logic. The flaw is triggered when the server processes a specially crafted XKB request from a local client. Because the server fails to properly validate the request parameters, it may access memory outside of the intended buffer. This can result in a server crash (Denial of Service) or the exposure of sensitive memory contents to the local attacker. The vulnerability affects standard X.Org servers, Xwayland, and TigerVNC components that incorporate X server code. Patches have been released by major distributions including Red Hat.

Affected products

X.Org X server All versions prior to April 2026 patches
X.Org Xwayland
TigerVNC TigerVNC

Timeline

2026-04-23: disclosed: CVE published and reported by Red Hat
2026-04-27: patched: Red Hat released security updates for RHEL 9 (RHSA-2026:10739)
2026-04-28: patched: Red Hat released security updates for RHEL 10 (RHSA-2026:11352)

References

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