{"id":"CVE-2026-80961","title":"dm-pcache: validate kset key_num and intra-segment bounds","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm-pcache: validate kset key_num and intra-segment bounds\n\nTwo more fields decoded from the cache device go unbounded. The kset\nkey_num drives cache_kset_crc() and the …","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","cvssSource":"cna","cwe":["CWE-125"],"vendor":"Linux","product":"Linux","affected":["Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < d8caf96040a06096276ab72f5e1e8547c014c564","Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < 5ac38f4b4862fad6e7270fde5c3356a822ce74ca","Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < f11deb032fd84081e7831cffcba895d893054a22","Linux 6.18"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:45:45.271Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-80961","references":[{"url":"https://git.kernel.org/stable/c/d8caf96040a06096276ab72f5e1e8547c014c564"},{"url":"https://git.kernel.org/stable/c/5ac38f4b4862fad6e7270fde5c3356a822ce74ca"},{"url":"https://git.kernel.org/stable/c/f11deb032fd84081e7831cffcba895d893054a22"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80961.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-80961"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532021"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80961"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80961"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80961.mbox"}],"tags":["cve.org","csaf","vex","red-hat","score-dispute"],"epss":0.00173,"epssPercentile":0.06736,"scores":{"cna":7.8,"vendor":5.5},"ingestedAt":"2026-09-14T15:23:07.476Z","slug":"CVE-2026-80961","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ndm-pcache: validate kset key_num and intra-segment bounds\n\nTwo more fields decoded from the cache device go unbounded. The kset\nkey_num drives cache_kset_crc() and the replay loop in cache_replay(),\nthe writeback worker and the GC worker, but only the magic and a\nfixed-seed CRC are checked first, so a non-last kset whose key_num exceeds\nthe PCACHE_KSET_KEYS_MAX buffer reads past its end before the CRC compare.\nA key's intra-segment offset and length in cache_key_decode() are taken\nverbatim, so a key running past its segment is replayed into the cache\ntree and the data CRC check and every later read hit then copy adjacent\npersistent memory into the caller's bio -- an out-of-bounds read that\nleaks to user space. Both fields are controlled by whoever supplies the\ncache device (CAP_SYS_ADMIN); the CRC seed is public.\n\nAdd kset_onmedia_valid() to bound key_num before any kset read, and\nreject a key whose offset plus length, computed in 64 bits, exceeds the\nsegment data_size. Valid metadata is unaffected.\n\n## Affected\n\n- `Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < d8caf96040a06096276ab72f5e1e8547c014c564`\n- `Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < 5ac38f4b4862fad6e7270fde5c3356a822ce74ca`\n- `Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < f11deb032fd84081e7831cffcba895d893054a22`\n- `Linux 6.18`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80961.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":224808,"id":"CVE-2026-80961","ts":1792401556140,"field":"cvss","old":"5.5","new":"7.8"},{"seq":224807,"id":"CVE-2026-80961","ts":1792401556140,"field":"severity","old":"medium","new":"high"},{"seq":202802,"id":"CVE-2026-80961","ts":1789403723672,"field":"cvss","old":"7.8","new":"5.5"},{"seq":202801,"id":"CVE-2026-80961","ts":1789403723672,"field":"severity","old":"high","new":"medium"},{"seq":183608,"id":"CVE-2026-80961","ts":1789356676085,"field":"cvss","old":"7.8","new":"2.3"},{"seq":183607,"id":"CVE-2026-80961","ts":1789356676085,"field":"severity","old":"high","new":"low"},{"seq":153146,"id":"CVE-2026-80961","ts":1789285349232,"field":"cvss","old":null,"new":"7.8"},{"seq":153145,"id":"CVE-2026-80961","ts":1789285349232,"field":"severity","old":"none","new":"high"},{"seq":109626,"id":"CVE-2026-80961","ts":1789183732698,"field":"cvss","old":null,"new":"2.3"},{"seq":109625,"id":"CVE-2026-80961","ts":1789183732698,"field":"severity","old":"none","new":"low"}]}