{"api_version":"1","generated_at":"2026-09-14T04:31:50+00:00","cve":"CVE-2026-80961","urls":{"html":"https://cve.report/CVE-2026-80961","api":"https://cve.report/api/cve/CVE-2026-80961.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-80961","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80961"},"summary":{"title":"dm-pcache: validate kset key_num and intra-segment bounds","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:01","updated_at":"2026-09-13 07:17:03"},"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/5ac38f4b4862fad6e7270fde5c3356a822ce74ca","name":"https://git.kernel.org/stable/c/5ac38f4b4862fad6e7270fde5c3356a822ce74ca","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f11deb032fd84081e7831cffcba895d893054a22","name":"https://git.kernel.org/stable/c/f11deb032fd84081e7831cffcba895d893054a22","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d8caf96040a06096276ab72f5e1e8547c014c564","name":"https://git.kernel.org/stable/c/d8caf96040a06096276ab72f5e1e8547c014c564","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80961","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80961","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 d8caf96040a06096276ab72f5e1e8547c014c564 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 5ac38f4b4862fad6e7270fde5c3356a822ce74ca git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 f11deb032fd84081e7831cffcba895d893054a22 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":"80961","cve":"CVE-2026-80961","epss":"0.001610000","percentile":"0.056700000","score_date":"2026-09-13","updated_at":"2026-09-14 00:18:01"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/md/dm-pcache/cache.h","drivers/md/dm-pcache/cache_gc.c","drivers/md/dm-pcache/cache_key.c","drivers/md/dm-pcache/cache_writeback.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"d8caf96040a06096276ab72f5e1e8547c014c564","status":"affected","version":"1d57628ff95b32d5cfa8d8f50e07690c161e9cf0","versionType":"git"},{"lessThan":"5ac38f4b4862fad6e7270fde5c3356a822ce74ca","status":"affected","version":"1d57628ff95b32d5cfa8d8f50e07690c161e9cf0","versionType":"git"},{"lessThan":"f11deb032fd84081e7831cffcba895d893054a22","status":"affected","version":"1d57628ff95b32d5cfa8d8f50e07690c161e9cf0","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/md/dm-pcache/cache.h","drivers/md/dm-pcache/cache_gc.c","drivers/md/dm-pcache/cache_key.c","drivers/md/dm-pcache/cache_writeback.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: 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."}],"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 bugs are reached only via local device-mapper ioctls on /dev/mapper/control (ctl_ioctl → table_load → dm_pcache_ctr → pcache_cache_start → cache_replay) and the subsequent local GC/writeback workers and bio map path; no network protocol or physical-bus input feeds kset/key decode.\nAC:L - The attacker fully controls the DAX cache image; kset CRC uses public PCACHE_CRC_SEED 0x3B15A, so a non-last kset with key_num > 128 and keys whose cache_seg_off+len exceed the segment are encoded and replayed deterministically on table load with no race or victim-side state.\nPR:L - ctl_ioctl gates DM_TABLE_LOAD with capable(CAP_SYS_ADMIN), which per kernel CNA guidance is obtainable inside an unprivileged user namespace and in storage containers with delegated mapper/DAX nodes, so this is Low rather than 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, then optional reads of the mapped device; no separate victim must mount media or open files.\nS:U - The out-of-bounds kset/key access corrupts and discloses memory inside the host kernel that loaded the pcache table; it does not cross a VM, hypervisor, IOMMU, or other separate security-authority boundary.\nC:H - cache_kset_crc() reads struct_size(..., key_num) bytes from a buffer sized for 128 keys, an unbounded kernel-heap OOB read; keys with unchecked cache_seg_off+len are then copied by segment_copy_to_bio() from adjacent pmem/kernel memory into the caller's bio, leaking to userspace.\nI:H - Replay inserts those OOB keys into the cache tree; writeback then copies from the attacker-chosen cache addresses onto the backing device, and later cut/advance of those keys operates on corrupted cache_pos. This OOB memory-corruption class is Integrity High under kernel CNA guidance.\nA:H - An oversized key_num makes crc32c walk off the kset buffer into unmapped heap, writeback BUG_ON(seg_remain < key->len), and cache_pos_advance() BUG_ON or a copy past the DAX mapping can oops or panic the kernel, causing system-wide denial of service."}]}],"providerMetadata":{"dateUpdated":"2026-09-13T06:28:32.873Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"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"}],"title":"dm-pcache: validate kset key_num and intra-segment bounds","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-80961","datePublished":"2026-09-11T19:42:27.847Z","dateReserved":"2026-08-26T14:34:25.809Z","dateUpdated":"2026-09-13T06:28:32.873Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:01","lastModifiedDate":"2026-09-13 07:17:03","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":"80961","Ordinal":"1","Title":"dm-pcache: validate kset key_num and intra-segment bounds","CVE":"CVE-2026-80961","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80961","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"dm-pcache: validate kset key_num and intra-segment bounds"}]}}}