{"id":"CVE-2021-35477","title":"In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occu…","summary":"In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occu…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","cwe":["CWE-203"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel <= 5.13.7","debian_linux = 9.0","fedora = 33","fedora = 34"],"published":"2021-08-02","updated":"2026-10-08","sourceUpdated":"2026-10-08T21:17:36.503","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2021-35477","references":[{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/?id=2039f26f3aca5b0e419b98f65dd36481337b86ee","label":"cve@mitre.org"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/?id=f5e81d1117501546b7be050c5fbafa6efd2c722c","label":"cve@mitre.org"},{"url":"https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/565ZS55ZFEN62WVRRORT7R63RXW5F4T4/","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6JKK6XNRZX5BT5QVYOKGVJ2BHFZAP5EX/","label":"cve@mitre.org"},{"url":"https://www.openwall.com/lists/oss-security/2021/08/01/3","label":"cve@mitre.org"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/?id=2039f26f3aca5b0e419b98f65dd36481337b86ee","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/?id=f5e81d1117501546b7be050c5fbafa6efd2c722c","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/565ZS55ZFEN62WVRRORT7R63RXW5F4T4/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6JKK6XNRZX5BT5QVYOKGVJ2BHFZAP5EX/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.openwall.com/lists/oss-security/2021/08/01/3","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.0046,"epssPercentile":0.37834,"ingestedAt":"2026-10-08T22:11:53.738Z","slug":"CVE-2021-35477","body":"## Overview\n\nIn the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occur before a store operation that has an attacker-controlled value.\n\n## Affected\n\n- `linux_kernel <= 5.13.7`\n- `debian_linux = 9.0`\n- `fedora = 33`\n- `fedora = 34`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}