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Vulnerability · Published Feb 28, 2024 · Assigned by Linux

CVE-2021-46993sched: Fix out-of-bound access in uclamp

High 7.8

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.2%top 84.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.10.38-1DEBIAN-CVE-2021-46993
Debian:13linux5.10.38-1DEBIAN-CVE-2021-46993
Debian:14linux5.10.38-1DEBIAN-CVE-2021-46993
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2021-46993
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2021-46993
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2021-46993

Affected products (as reported)

VendorProductVersions
Linux Linux 69842cba9ace84849bb9b8edcdf2cefccd97901c – before 687f523c134b7f0bd040ee1230f6d17990d5417269842cba9ace84849bb9b8edcdf2cefccd97901c – before f7347c85490b92dd144fa1fba9e1eca501656ab369842cba9ace84849bb9b8edcdf2cefccd97901c – before 3da3f804b82a0a382d523a21acf4cf3bb35f936d69842cba9ace84849bb9b8edcdf2cefccd97901c – before 42ee47c7e3569d9a0e2cb5053c496d97d380472f69842cba9ace84849bb9b8edcdf2cefccd97901c – before 6d2f8909a5fabb73fe2a63918117943986c39b6c
Linux Linux 5.3

References