CVE-2021-20317: Debian Linux

Medium severity, CVSS 4.4. EPSS: 0.4% chance of exploitation in the next 30 days.

A flaw was found in the Linux kernel. A corrupted timer tree caused the task wakeup to be missing in the timerqueue_add function in lib/timerqueue.c. This flaw allows a local attacker with special user privileges to cause a denial of service, slowing and eventually stopping the system while running OSP.

Affected products

• Debian Debian Linux: version 9.0 only; version 10.0 only
• Linux Linux Kernel: before 5.4 (fixed in 5.4); version 5.4 only

Published 2021-09-27. Last modified 2026-06-17.