CVE-2021-46993

sched: Fix out-of-bound access in uclamp

HIGH
7.1
CVSS Score
Published: February 28, 2024 at 08:13 AM UTC
Updated: August 5, 2026 at 09:24 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.1
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.11 ≤ v < 5.11.225.12 ≤ v < 5.12.55.3 ≤ v < 5.10.385.3 ≤ v < 5.11.225.3 ≤ v < 5.12.55.3 ≤ v < 5.135.3 ≤ v < 5.4.1205.5 ≤ v < 5.10.385.369842cba9ace84849bb9b8edcdf2cefccd97901c
Vendor states this is fixed in 3da3f804b82a0a382d523a21acf4cf3bb35f936d (fixed)
Vendor states this is fixed in 42ee47c7e3569d9a0e2cb5053c496d97d380472f (fixed)
Vendor states this is fixed in 687f523c134b7f0bd040ee1230f6d17990d54172 (fixed)
Vendor states this is fixed in 6d2f8909a5fabb73fe2a63918117943986c39b6c (fixed)
Vendor states this is fixed in f7347c85490b92dd144fa1fba9e1eca501656ab3 (fixed)
Vendor states this is fixed in 5.10.38 (unaffected)
Vendor states this is fixed in 5.11.22 (unaffected)
Vendor states this is fixed in 5.12.5 (unaffected)
Vendor states this is fixed in 5.13 (unaffected)
Vendor states this is fixed in 5.3 (unaffected)
Vendor states this is fixed in 5.4.120 (unaffected)

References (5)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/3da3f804b82a0a382d523a21acf4cf3bb35f936d
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/42ee47c7e3569d9a0e2cb5053c496d97d380472f
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/687f523c134b7f0bd040ee1230f6d17990d54172
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/6d2f8909a5fabb73fe2a63918117943986c39b6c
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/f7347c85490b92dd144fa1fba9e1eca501656ab3

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-125

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