{"api_version":"1","generated_at":"2026-09-15T05:44:04+00:00","cve":"CVE-2026-80955","urls":{"html":"https://cve.report/CVE-2026-80955","api":"https://cve.report/api/cve/CVE-2026-80955.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-80955","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80955"},"summary":{"title":"dm-pcache: fix use-after-free and invalid seg operations in kset_replay()","description":"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), 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seg_map bit\nand calling cache_seg_get() is unreasonable since the corresponding\nsegment data is no longer valid.\n\nFix both issues by moving cache_seg_get() and __set_bit() after the\ngen check, so they only execute for valid keys, and using continue to\nskip invalid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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:01","updated_at":"2026-09-13 07:17:02"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/1894fc7a3bab90143dcd26ef8ee27040ef4a7501","name":"https://git.kernel.org/stable/c/1894fc7a3bab90143dcd26ef8ee27040ef4a7501","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c2e894eac398b258f12fdec73ed6ba081047f7b3","name":"https://git.kernel.org/stable/c/c2e894eac398b258f12fdec73ed6ba081047f7b3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f39a3e9cc5946473e16d6f5071b2ee0216c56d06","name":"https://git.kernel.org/stable/c/f39a3e9cc5946473e16d6f5071b2ee0216c56d06","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80955","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80955","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 1894fc7a3bab90143dcd26ef8ee27040ef4a7501 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 f39a3e9cc5946473e16d6f5071b2ee0216c56d06 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 c2e894eac398b258f12fdec73ed6ba081047f7b3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.50 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.4 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"80955","cve":"CVE-2026-80955","epss":"0.001570000","percentile":"0.052010000","score_date":"2026-09-14","updated_at":"2026-09-15 00:00:42"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/md/dm-pcache/cache_key.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"1894fc7a3bab90143dcd26ef8ee27040ef4a7501","status":"affected","version":"1d57628ff95b32d5cfa8d8f50e07690c161e9cf0","versionType":"git"},{"lessThan":"f39a3e9cc5946473e16d6f5071b2ee0216c56d06","status":"affected","version":"1d57628ff95b32d5cfa8d8f50e07690c161e9cf0","versionType":"git"},{"lessThan":"c2e894eac398b258f12fdec73ed6ba081047f7b3","status":"affected","version":"1d57628ff95b32d5cfa8d8f50e07690c161e9cf0","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/md/dm-pcache/cache_key.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.18"},{"lessThan":"6.18","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.50","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.50","versionStartIncluding":"6.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.4","versionStartIncluding":"6.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"6.18","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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), 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."}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - The UAF is reached only via local device-mapper ioctls on /dev/mapper/control (ctl_ioctl → table_load → dm_pcache_ctr → pcache_start → pcache_cache_start → cache_init_req_keys → cache_replay → kset_replay). No network, Bluetooth, or physical-bus path feeds this replay code.\nAC:L - The attacker fully controls the DAX cache-device image, including kset records (CRC uses public PCACHE_CRC_SEED 0x3B15A) and per-segment gen metadata, so they can deterministically encode keys with seg_gen < cache_seg->gen and hit the free-then-use on every table load; no race or victim-side state is required.\nPR:L - ctl_ioctl gates DM_TABLE_LOAD with capable(CAP_SYS_ADMIN), which is obtainable inside an unprivileged user namespace (and in storage containers with delegated mapper/DAX nodes); per kernel CNA guidance that is Low, not init-namespace root only.\nUI:N - Exploitation requires only the attacker's own dmsetup/DM_TABLE_LOAD of a pcache target whose cache device holds crafted INIT_DONE ksets; no separate victim must mount media, open a file, or otherwise interact.\nS:U - The use-after-free is of a pcache_cache_key in the req_key_tree mempool and of cache seg_map/segment refcounts inside the host kernel; it does not cross a VM, hypervisor, IOMMU, or other separate security-authority boundary.\nC:H - On a stale key, cache_key_put() mempool-frees the decoded pcache_cache_key and kset_replay then reads key->cache_pos.cache_seg from that freed heap object. A kernel UAF of a slab/mempool object enables reclaim and an arbitrary read primitive, so confidentiality is High.\nI:H - The dangling key is passed to cache_seg_get(), which atomic_inc()s refs on the pointer loaded from freed memory, and the stale path also __set_bit()s cache->seg_map before the gen check. That UAF write/refcount primitive is Integrity High and is exploitable for control-flow hijack after spraying.\nA:H - Using the freed cache key (and inflating segment refs plus seg_map bits for invalid keys) can oops or panic on poisoned/reused mempool memory or under KASAN/slub debug; any kernel crash from this UAF is Availability High."}]}],"providerMetadata":{"dateUpdated":"2026-09-13T06:28:29.166Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"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"}],"title":"dm-pcache: fix use-after-free and invalid seg operations in kset_replay()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-80955","datePublished":"2026-09-11T19:42:23.838Z","dateReserved":"2026-08-26T14:34:25.804Z","dateUpdated":"2026-09-13T06:28:29.166Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:01","lastModifiedDate":"2026-09-13 07:17:02","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"80955","Ordinal":"1","Title":"dm-pcache: fix use-after-free and invalid seg operations in kset","CVE":"CVE-2026-80955","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80955","Ordinal":"1","NoteData":"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), 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.","Type":"Description","Title":"dm-pcache: fix use-after-free and invalid seg operations in kset"}]}}}