CVE-2021-20321: Debian Linux

Medium severity, CVSS 4.7. EPSS: 0.2% chance of exploitation in the next 30 days.

A race condition accessing file object in the Linux kernel OverlayFS subsystem was found in the way users do rename in specific way with OverlayFS. A local user could use this flaw to crash the system.

Affected products

• Debian Debian Linux: version 9.0 only; version 10.0 only
• Linux Linux Kernel: before 5.15 (fixed in 5.15); version 5.15 only
• Red Hat Enterprise Linux: version 7.0 only; version 8.0 only

Published 2022-02-18. Last modified 2026-06-17.