CVE-2021-46993

HIGH

Linux Kernel - Out-of-bounds Read in uclamp Bucket Index Calculation

Title source: llm
STIX 2.1

Description

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.

Scores

CVSS v3 7.1
EPSS 0.0024
EPSS Percentile 15.1%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-125
Status published
Products (13)
Linux/Linux < 5.3
Linux/Linux 5.10.38 - 5.10.*
Linux/Linux 5.11.22 - 5.11.*
Linux/Linux 5.12.5 - 5.12.*
Linux/Linux 5.13
Linux/Linux 5.3
Linux/Linux 5.4.120 - 5.4.*
Linux/Linux 69842cba9ace84849bb9b8edcdf2cefccd97901c - 3da3f804b82a0a382d523a21acf4cf3bb35f936d
Linux/Linux 69842cba9ace84849bb9b8edcdf2cefccd97901c - 42ee47c7e3569d9a0e2cb5053c496d97d380472f
Linux/Linux 69842cba9ace84849bb9b8edcdf2cefccd97901c - 687f523c134b7f0bd040ee1230f6d17990d54172
... and 3 more
Published Feb 28, 2024
Tracked Since Feb 18, 2026