{"id":"CVE-2026-80961","summary":"dm-pcache: validate kset key_num and intra-segment bounds","details":"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 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.","modified":"2026-09-14T03:45:49.748940600Z","published":"2026-09-11T19:42:27.847Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80961.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/5ac38f4b4862fad6e7270fde5c3356a822ce74ca"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d8caf96040a06096276ab72f5e1e8547c014c564"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f11deb032fd84081e7831cffcba895d893054a22"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80961.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80961"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"1d57628ff95b32d5cfa8d8f50e07690c161e9cf0"},{"fixed":"d8caf96040a06096276ab72f5e1e8547c014c564"},{"fixed":"5ac38f4b4862fad6e7270fde5c3356a822ce74ca"},{"fixed":"f11deb032fd84081e7831cffcba895d893054a22"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80961.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.18.0"},{"fixed":"6.18.50"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80961.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}