{"id":"CVE-2021-46993","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched: Fix out-of-bound access in uclamp\n\nUtil-clamp places tasks in different buckets based on their clamp values\nfor performance reasons","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched: Fix out-of-bound access in uclamp\n\nUtil-clamp places tasks in different buckets based on their clamp values\nfor performance reasons. However, the size of buckets…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-125"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.3, < 5.4.120","linux_kernel >= 5.5, < 5.10.38","linux_kernel >= 5.11, < 5.11.22","linux_kernel >= 5.12, < 5.12.5"],"patched":["linux_kernel 5.12.5"],"published":"2024-02-28","updated":"2026-08-04","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2021-46993","references":[{"url":"https://git.kernel.org/stable/c/3da3f804b82a0a382d523a21acf4cf3bb35f936d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/42ee47c7e3569d9a0e2cb5053c496d97d380472f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/687f523c134b7f0bd040ee1230f6d17990d54172","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6d2f8909a5fabb73fe2a63918117943986c39b6c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f7347c85490b92dd144fa1fba9e1eca501656ab3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3da3f804b82a0a382d523a21acf4cf3bb35f936d","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/42ee47c7e3569d9a0e2cb5053c496d97d380472f","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/687f523c134b7f0bd040ee1230f6d17990d54172","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/6d2f8909a5fabb73fe2a63918117943986c39b6c","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/f7347c85490b92dd144fa1fba9e1eca501656ab3","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.00241,"epssPercentile":0.15543,"ingestedAt":"2026-08-04T10:39:38.942Z","slug":"CVE-2021-46993","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nsched: Fix out-of-bound access in uclamp\n\nUtil-clamp places tasks in different buckets based on their clamp values\nfor performance reasons. However, the size of buckets is currently\ncomputed using a rounding division, which can lead to an off-by-one\nerror in some configurations.\n\nFor instance, with 20 buckets, the bucket size will be 1024/20=51. A\ntask with a clamp of 1024 will be mapped to bucket id 1024/51=20. Sadly,\ncorrect indexes are in range [0,19], hence leading to an out of bound\nmemory access.\n\nClamp the bucket id to fix the issue.\n\n## Affected\n\n- `linux_kernel >= 5.3, < 5.4.120`\n- `linux_kernel >= 5.5, < 5.10.38`\n- `linux_kernel >= 5.11, < 5.11.22`\n- `linux_kernel >= 5.12, < 5.12.5`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 5.12.5`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}