{"id":"CVE-2021-38166","title":"In kernel/bpf/hashtab.c in the Linux kernel through 5.13.8, there is an integer overflow and out-of-bounds write when many elements are placed in a single bucket","summary":"In kernel/bpf/hashtab.c in the Linux kernel through 5.13.8, there is an integer overflow and out-of-bounds write when many elements are placed in a single bucket. NOTE: exploitation might be impractical without the CAP_SYS_ADMIN capability.","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-190","CWE-787"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.6, < 5.10.60","linux_kernel >= 5.11, < 5.13.12","fedora = 33","fedora = 34","debian_linux = 11.0"],"patched":["linux_kernel 5.13.12"],"published":"2021-08-07","updated":"2026-08-05","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2021-38166","references":[{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=c4eb1f403243fc7bbb7de644db8587c03de36da6","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GUVLBJKZMWA3E3YXSH4SZ7BOYGJP4GXP/","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UL6CH5M5PRLMA3KPBX4LPUO6Z73GRISO/","label":"cve@mitre.org"},{"url":"https://lore.kernel.org/bpf/20210806150419.109658-1-th.yasumatsu%40gmail.com/","label":"cve@mitre.org"},{"url":"https://security.netapp.com/advisory/ntap-20210909-0001/","label":"cve@mitre.org"},{"url":"https://www.debian.org/security/2021/dsa-4978","label":"cve@mitre.org"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=c4eb1f403243fc7bbb7de644db8587c03de36da6","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GUVLBJKZMWA3E3YXSH4SZ7BOYGJP4GXP/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UL6CH5M5PRLMA3KPBX4LPUO6Z73GRISO/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lore.kernel.org/bpf/20210806150419.109658-1-th.yasumatsu%40gmail.com/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20210909-0001/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2021/dsa-4978","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.00315,"epssPercentile":0.2466,"ingestedAt":"2026-08-05T18:50:24.844Z","slug":"CVE-2021-38166","body":"## Overview\n\nIn kernel/bpf/hashtab.c in the Linux kernel through 5.13.8, there is an integer overflow and out-of-bounds write when many elements are placed in a single bucket. NOTE: exploitation might be impractical without the CAP_SYS_ADMIN capability.\n\n## Affected\n\n- `linux_kernel >= 5.6, < 5.10.60`\n- `linux_kernel >= 5.11, < 5.13.12`\n- `fedora = 33`\n- `fedora = 34`\n- `debian_linux = 11.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 5.13.12`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}