CVE-2026-50263 in X11 Server

Summary

by MITRE • 06/05/2026

A use-after-free flaw was found in the X.Org X server and Xwayland in CreateSaverWindow(). A client can trigger a use-after-free read after changing window attributes and forcing the screen saver, leading to information disclosure.

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• Responsible: Redhat
• Reservation: 06/04/2026
• Disclosure: 06/05/2026
• Moderation: accepted
• Entry: VDB-368919
• CPE: ready
• CWE: CWE-416 (confirmed)
• CVSS: 5.5 (CNA)
• EPSS: 0.00012
• KEV: no
• Activities: low
• Sector: Chemical, Transportation, ...

Sources

• MITRE: https://www.cve.org/CVERecord?id=CVE-2026-50263
• NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-50263
• CVE Details: https://www.cvedetails.com/cve/CVE-2026-50263/