{"id":"CVE-2026-80960","title":"dm-pcache: validate on-media seg_num against the cache device size","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm-pcache: validate on-media seg_num against the cache device size\n\nseg_num is read from the crc32c-only superblock, so whoever supplies the\ncache device on a table loa…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":["CWE-787"],"vendor":"Linux","product":"Linux","affected":["Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < 91b93fe5cf4d62d5ecc642a6c8f15a3c11b00e3c","Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < e889c0ee81165fc90aad2979b51f930f77895703","Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < 62d92e45abe9e087370f9fc5d876b95673aced34","Linux 6.18"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:45:44.213Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-80960","references":[{"url":"https://git.kernel.org/stable/c/91b93fe5cf4d62d5ecc642a6c8f15a3c11b00e3c"},{"url":"https://git.kernel.org/stable/c/e889c0ee81165fc90aad2979b51f930f77895703"},{"url":"https://git.kernel.org/stable/c/62d92e45abe9e087370f9fc5d876b95673aced34"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80960.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-80960"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532483"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80960"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80960"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80960.mbox"}],"tags":["cve.org","csaf","vex","red-hat"],"epss":0.00206,"epssPercentile":0.1061,"ingestedAt":"2026-09-14T00:35:28.532Z","slug":"CVE-2026-80960","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ndm-pcache: validate on-media seg_num against the cache device size\n\nseg_num is read from the crc32c-only superblock, so whoever supplies the\ncache device on a table load (CAP_SYS_ADMIN) controls it. It sizes\ncache->segments[] and is the value every later on-media segment id is\nbounded against, yet it is never checked against the device. Because\ncache_dev->mapping is the direct map of the pmem, CACHE_DEV_SEGMENT() for\na segment id past the device resolves to ordinary kernel memory beyond\nthe mapping; a new-cache init reaching such an id has cache_seg_init() ->\ncache_dev_zero_range() memset() 12 KiB over that memory -- an\nout-of-bounds write into the kernel heap at table load. A zero seg_num\nmakes the segment allocations ZERO_SIZE_PTR.\n\nReject a seg_num that is zero, larger than the device can hold, or larger\nthan PCACHE_CACHE_SEGS_MAX before it is used.\n\n## Affected\n\n- `Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < 91b93fe5cf4d62d5ecc642a6c8f15a3c11b00e3c`\n- `Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < e889c0ee81165fc90aad2979b51f930f77895703`\n- `Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < 62d92e45abe9e087370f9fc5d876b95673aced34`\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 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80960.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":204234,"id":"CVE-2026-80960","ts":1789490240439,"field":"cvss","old":null,"new":"5.5"},{"seq":204233,"id":"CVE-2026-80960","ts":1789490240439,"field":"severity","old":"none","new":"medium"},{"seq":147133,"id":"CVE-2026-80960","ts":1789270195956,"field":"cvss","old":null,"new":"5.7"},{"seq":147132,"id":"CVE-2026-80960","ts":1789270195956,"field":"severity","old":"none","new":"medium"},{"seq":108886,"id":"CVE-2026-80960","ts":1789183729407,"field":"cvss","old":null,"new":"5.7"},{"seq":108885,"id":"CVE-2026-80960","ts":1789183729407,"field":"severity","old":"none","new":"medium"}]}