{"id":"CVE-2020-27171","title":"An issue was discovered in the Linux kernel before 5.11.8","summary":"An issue was discovered in the Linux kernel before 5.11.8. kernel/bpf/verifier.c has an off-by-one error (with a resultant integer underflow) affecting out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that…","severity":"medium","cvss":6,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H","cwe":["CWE-193"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel < 5.11.8","fedora = 32","fedora = 33","fedora = 34","debian_linux = 9.0","ubuntu_linux = 14.04","ubuntu_linux = 16.04","ubuntu_linux = 18.04","ubuntu_linux = 20.04"],"patched":["linux_kernel 5.11.8"],"published":"2021-03-20","updated":"2026-10-08","sourceUpdated":"2026-10-08T21:17:27.333","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2020-27171","references":[{"url":"http://packetstormsecurity.com/files/162117/Kernel-Live-Patch-Security-Notice-LSN-0075-1.html","label":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2021/03/24/5","label":"cve@mitre.org"},{"url":"https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.8","label":"cve@mitre.org"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/patch/?id=10d2bb2e6b1d8c4576c56a748f697dbeb8388899","label":"cve@mitre.org"},{"url":"https://lists.debian.org/debian-lts-announce/2021/03/msg00035.html","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FB6LUXPEIRLZH32YXWZVEZAD4ZL6SDK2/","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QRTPQE73ANG7D6M4L4PK5ZQDPO4Y2FVD/","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T2S3I4SLRNRUQDOFYUS6IUAZMQNMPNLG/","label":"cve@mitre.org"},{"url":"https://www.openwall.com/lists/oss-security/2021/03/19/3","label":"cve@mitre.org"},{"url":"http://packetstormsecurity.com/files/162117/Kernel-Live-Patch-Security-Notice-LSN-0075-1.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2021/03/24/5","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.8","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/patch/?id=10d2bb2e6b1d8c4576c56a748f697dbeb8388899","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2021/03/msg00035.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FB6LUXPEIRLZH32YXWZVEZAD4ZL6SDK2/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QRTPQE73ANG7D6M4L4PK5ZQDPO4Y2FVD/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T2S3I4SLRNRUQDOFYUS6IUAZMQNMPNLG/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.openwall.com/lists/oss-security/2021/03/19/3","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd","cve.org"],"epss":0.00577,"epssPercentile":0.47356,"ingestedAt":"2026-10-08T22:11:53.730Z","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-08T20:57:10.613050Z"},"slug":"CVE-2020-27171","body":"## Overview\n\nAn issue was discovered in the Linux kernel before 5.11.8. kernel/bpf/verifier.c has an off-by-one error (with a resultant integer underflow) affecting out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory, aka CID-10d2bb2e6b1d.\n\n## Affected\n\n- `linux_kernel < 5.11.8`\n- `fedora = 32`\n- `fedora = 33`\n- `fedora = 34`\n- `debian_linux = 9.0`\n- `ubuntu_linux = 14.04`\n- `ubuntu_linux = 16.04`\n- `ubuntu_linux = 18.04`\n- `ubuntu_linux = 20.04`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 5.11.8`","depth":"sunlit","depthScore":33,"depthScoreParts":{"impact":33,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}