CVE-2021-4008: Debian Linux

High severity, CVSS 7.8. EPSS: 0.6% chance of exploitation in the next 30 days.

A flaw was found in xorg-x11-server in versions before 21.1.2 and before 1.20.14. An out-of-bounds access can occur in the SProcRenderCompositeGlyphs function. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Affected products

• Debian Debian Linux: version 9.0 only; version 10.0 only; version 11.0 only
• Fedoraproject Fedora: version 34 only; version 35 only
• X.org X Server: before 1.20.14 (fixed in 1.20.14); version 21.1.0 only; version 21.1.1 only

Published 2021-12-17. Last modified 2026-06-17.