{"id":"CVE-2026-80955","title":"dm-pcache: fix use-after-free and invalid seg operations in kset_replay()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm-pcache: fix use-after-free and invalid seg operations in kset_replay()\n\nIn kset_replay, when key->seg_gen is stale (key->seg_gen <\nkey->cache_pos.cache_seg->gen), ca…","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-825"],"vendor":"Linux","product":"Linux","affected":["Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < 1894fc7a3bab90143dcd26ef8ee27040ef4a7501","Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < f39a3e9cc5946473e16d6f5071b2ee0216c56d06","Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < c2e894eac398b258f12fdec73ed6ba081047f7b3","Linux 6.18"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:45:39.156Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-80955","references":[{"url":"https://git.kernel.org/stable/c/1894fc7a3bab90143dcd26ef8ee27040ef4a7501"},{"url":"https://git.kernel.org/stable/c/f39a3e9cc5946473e16d6f5071b2ee0216c56d06"},{"url":"https://git.kernel.org/stable/c/c2e894eac398b258f12fdec73ed6ba081047f7b3"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80955.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-80955"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532031"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80955"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80955"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80955.mbox"}],"tags":["cve.org","csaf","vex","red-hat","score-dispute"],"epss":0.00168,"epssPercentile":0.06141,"scores":{"cna":7.8,"vendor":5.5},"ingestedAt":"2026-09-14T15:23:07.476Z","slug":"CVE-2026-80955","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ndm-pcache: fix use-after-free and invalid seg operations in kset_replay()\n\nIn kset_replay, when key->seg_gen is stale (key->seg_gen <\nkey->cache_pos.cache_seg->gen), cache_key_put(key) is called but then\nkey->cache_pos.cache_seg is accessed as the argument to cache_seg_get().\nThis is a use-after-free on the freed key memory. Although mempool\nrecycled memory is not immediately reclaimed or overwritten in practice,\nthis is still a potential UAF bug.\n\nAdditionally, for expired invalid keys, setting the cache->seg_map bit\nand calling cache_seg_get() is unreasonable since the corresponding\nsegment data is no longer valid.\n\nFix both issues by moving cache_seg_get() and __set_bit() after the\ngen check, so they only execute for valid keys, and using continue to\nskip invalid keys.\n\n## Affected\n\n- `Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < 1894fc7a3bab90143dcd26ef8ee27040ef4a7501`\n- `Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < f39a3e9cc5946473e16d6f5071b2ee0216c56d06`\n- `Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < c2e894eac398b258f12fdec73ed6ba081047f7b3`\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-2026-80955.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":224810,"id":"CVE-2026-80955","ts":1792401556998,"field":"cvss","old":"5.5","new":"7.8"},{"seq":224809,"id":"CVE-2026-80955","ts":1792401556998,"field":"severity","old":"medium","new":"high"},{"seq":202763,"id":"CVE-2026-80955","ts":1789403715785,"field":"cvss","old":"7.8","new":"5.5"},{"seq":202762,"id":"CVE-2026-80955","ts":1789403715785,"field":"severity","old":"high","new":"medium"},{"seq":183614,"id":"CVE-2026-80955","ts":1789356676109,"field":"cvss","old":"7.8","new":"4.7"},{"seq":183613,"id":"CVE-2026-80955","ts":1789356676109,"field":"severity","old":"high","new":"medium"},{"seq":153140,"id":"CVE-2026-80955","ts":1789285349207,"field":"cvss","old":null,"new":"7.8"},{"seq":153139,"id":"CVE-2026-80955","ts":1789285349207,"field":"severity","old":"none","new":"high"},{"seq":109634,"id":"CVE-2026-80955","ts":1789183732729,"field":"cvss","old":null,"new":"4.7"},{"seq":109633,"id":"CVE-2026-80955","ts":1789183732729,"field":"severity","old":"none","new":"medium"}]}