{"api_version":"1","generated_at":"2026-10-27T04:29:37+00:00","cve":"CVE-2026-99051","urls":{"html":"https://cve.report/CVE-2026-99051","api":"https://cve.report/api/cve/CVE-2026-99051.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-99051","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-99051"},"summary":{"title":"fsverity: RCU-delay the freeing of struct fsverity_info","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfsverity: RCU-delay the freeing of struct fsverity_info\n\n__fsverity_get_info() calls rhashtable_lookup_fast(), which just uses\nrcu_read_lock() and doesn't directly synchronize with\nfsverity_remove_info().\n\nFor the same inode this isn't a problem: its fsverity_info is removed\nonly at inode eviction time or upon failure to enable verity, when the\ninode no longer needs its fsverity_info and it will no longer be\naccessed via that inode.\n\nHowever, this is broken and can cause a use-after-free for concurrent\n__fsverity_get_info() for *different* inodes.  Those rely on following\nfsverity_info::rhash_head in the rhashtable under rcu_read_lock() only.\nThey also use fsverity_info::inode to do the key comparison.\n\nFix this by RCU-delaying the freeing of 'struct fsverity_info' after\nit's been removed from the rhashtable.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-23 13:17:28","updated_at":"2026-10-24 14:16:53"},"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/fa84f091a8e7fc46fd29834496fab9739dd4c8dc","name":"https://git.kernel.org/stable/c/fa84f091a8e7fc46fd29834496fab9739dd4c8dc","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e58c3805ed325fe2d4ae2dd467c0486cc860b733","name":"https://git.kernel.org/stable/c/e58c3805ed325fe2d4ae2dd467c0486cc860b733","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-99051","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99051","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f77f281b61183a5c0b87e6a4d101c70bd32c1c79 fa84f091a8e7fc46fd29834496fab9739dd4c8dc git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f77f281b61183a5c0b87e6a4d101c70bd32c1c79 e58c3805ed325fe2d4ae2dd467c0486cc860b733 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.0","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.11 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/verity/fsverity_private.h","fs/verity/open.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"fa84f091a8e7fc46fd29834496fab9739dd4c8dc","status":"affected","version":"f77f281b61183a5c0b87e6a4d101c70bd32c1c79","versionType":"git"},{"lessThan":"e58c3805ed325fe2d4ae2dd467c0486cc860b733","status":"affected","version":"f77f281b61183a5c0b87e6a4d101c70bd32c1c79","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/verity/fsverity_private.h","fs/verity/open.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"7.0"},{"lessThan":"7.0","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.11","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.11","versionStartIncluding":"7.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"7.0","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfsverity: RCU-delay the freeing of struct fsverity_info\n\n__fsverity_get_info() calls rhashtable_lookup_fast(), which just uses\nrcu_read_lock() and doesn't directly synchronize with\nfsverity_remove_info().\n\nFor the same inode this isn't a problem: its fsverity_info is removed\nonly at inode eviction time or upon failure to enable verity, when the\ninode no longer needs its fsverity_info and it will no longer be\naccessed via that inode.\n\nHowever, this is broken and can cause a use-after-free for concurrent\n__fsverity_get_info() for *different* inodes.  Those rely on following\nfsverity_info::rhash_head in the rhashtable under rcu_read_lock() only.\nThey also use fsverity_info::inode to do the key comparison.\n\nFix this by RCU-delaying the freeing of 'struct fsverity_info' after\nit's been removed from the rhashtable."}],"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 - `ioctl(FS_IOC_MEASURE_VERITY)` reaches `fsverity_ioctl_measure()` and `fsverity_get_info()`, while `unlinkat()`/`close()` of another fs-verity file reaches `clear_inode()`, `fsverity_cleanup_inode()`, and patched `fsverity_remove_info()`; these are local syscall paths, not wire data.\nAC:L - An attacker can enable many owned files to populate colliding rhashtable chains, then loop measurements of one inode while concurrently unlinking and closing the others; the attacker controls both lookup and freeing and can repeat the race.\nPR:L - `fsverity_ioctl_enable()` checks only `file_permission(filp, MAY_WRITE)`, `FMODE_READ`, and a writable mount, with no capability check; lookup and eviction require only ordinary access to attacker-owned files on btrfs or verity-enabled ext4/f2fs.\nUI:N - The attacker can create, enable, measure, unlink, and close all participating files using their own processes, without another user mounting media or taking any action.\nS:U - The dangling object belongs to the host kernel's `fsverity_info_hash` and `fsverity_info_cachep`; corrupting it affects the same kernel security authority and crosses no VM, IOMMU, or hypervisor boundary.\nC:H - `fsverity_remove_info()` frees the slab while `__rhashtable_lookup()` still reads `inode` and `rhash_head.next`; after cache reuse, a misdirected lookup is consumed by `fsverity_ioctl_measure()`, which dereferences `tree_params` and copies `file_digest` to userspace.\nI:H - File-read consumers pass the lookup result to `fsverity_verify_blocks()`, whose `clear_bit()` and `set_bit()` write through `vi->hash_block_verified`; attacker-groomed reuse of the freed object can therefore turn the UAF into arbitrary kernel-memory corruption.\nA:H - `kmem_cache_free()` permits allocator metadata to replace the freed `rhash_head.next` while the rhashtable loop still follows `pos->next`, which can oops or panic the kernel; repeated measure-and-evict cycles can retrigger it."}]}],"providerMetadata":{"dateUpdated":"2026-10-24T14:10:12.469Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/fa84f091a8e7fc46fd29834496fab9739dd4c8dc"},{"url":"https://git.kernel.org/stable/c/e58c3805ed325fe2d4ae2dd467c0486cc860b733"}],"title":"fsverity: RCU-delay the freeing of struct fsverity_info","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-99051","datePublished":"2026-10-23T12:22:30.370Z","dateReserved":"2026-09-25T10:25:14.388Z","dateUpdated":"2026-10-24T14:10:12.469Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-23 13:17:28","lastModifiedDate":"2026-10-24 14:16:53","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":"99051","Ordinal":"1","Title":"fsverity: RCU-delay the freeing of struct fsverity_info","CVE":"CVE-2026-99051","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"99051","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nfsverity: RCU-delay the freeing of struct fsverity_info\n\n__fsverity_get_info() calls rhashtable_lookup_fast(), which just uses\nrcu_read_lock() and doesn't directly synchronize with\nfsverity_remove_info().\n\nFor the same inode this isn't a problem: its fsverity_info is removed\nonly at inode eviction time or upon failure to enable verity, when the\ninode no longer needs its fsverity_info and it will no longer be\naccessed via that inode.\n\nHowever, this is broken and can cause a use-after-free for concurrent\n__fsverity_get_info() for *different* inodes.  Those rely on following\nfsverity_info::rhash_head in the rhashtable under rcu_read_lock() only.\nThey also use fsverity_info::inode to do the key comparison.\n\nFix this by RCU-delaying the freeing of 'struct fsverity_info' after\nit's been removed from the rhashtable.","Type":"Description","Title":"fsverity: RCU-delay the freeing of struct fsverity_info"}]}}}