CVE-2021-46993: Linux Kernel

High severity, CVSS 7.1. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: sched: Fix out-of-bound access in uclamp Util-clamp places tasks in different buckets based on their clamp values for performance reasons. However, the size of buckets is currently computed using a rounding division, which can lead to an off-by-one error in some configurations. For instance, with 20 buckets, the bucket size will be 1024/20=51. A task with a clamp of 1024 will be mapped to bucket id 1024/51=20. Sadly, correct indexes are in range [0,19], hence leading to an out of bound memory access. Clamp the bucket id to fix the issue.

Affected products

• Linux Linux Kernel: from 5.3, before 5.4.120 (fixed in 5.4.120); from 5.5, before 5.10.38 (fixed in 5.10.38); from 5.11, before 5.11.22 (fixed in 5.11.22); from 5.12, before 5.12.5 (fixed in 5.12.5)

Published 2024-02-28. Last modified 2026-08-04.