{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89667", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.745Z", "datePublished": "2026-09-11T19:45:53.609Z", "dateUpdated": "2026-10-19T08:50:40.641Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:50:40.641Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: close shrinker/GC/fsnotify vs per-net shutdown race in filecache\n\nThe shrinker, GC worker, and fsnotify/lease callbacks can unhash an\nnfsd_file from the rhashtable and then call\nnfsd_file_dispose_list_delayed() to move it to the per-net dispose list.\nIf nfsd_file_cache_shutdown_net() runs concurrently, its rhashtable walk\nmisses the already-unhashed file, and its drain of the per-net dispose\nlist can run before the file has been queued. The file then sits on\nthe per-net list with no thread to drain it, leaking both the file and\nits associated state.\n\nThe GC worker and shrinker already hold nfsd_gc_lock while walking the\nLRU, but in the original code they release it before calling\nnfsd_file_dispose_list_delayed(). The fsnotify/lease path\n(nfsd_file_close_inode) has no synchronization at all.\n\nFix this by:\n\n 1. Widening nfsd_gc_lock in both nfsd_file_gc() and nfsd_file_lru_scan()\n to cover the nfsd_file_dispose_list_delayed() call.\n\n 2. Wrapping nfsd_file_close_inode() in nfsd_gc_lock so that all three\n callers of nfsd_file_dispose_list_delayed() hold the lock.\n\n 3. Adding a spin_lock/unlock(nfsd_gc_lock) barrier in\n nfsd_file_cache_shutdown_net() after the purge, so that any\n in-progress disposal has fully completed before the per-net list\n is drained.\n\nAll operations inside the lock are non-sleeping (rhashtable lookups,\natomic bit/refcount ops, list moves, svc_wake_up), so the spinlock is\nappropriate." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable nfsd filecache GC, shrinker, and fsnotify close paths run in the in-kernel NFS server and are reached by NFS RPCs (OPEN/READ/WRITE/REMOVE) on TCP/UDP 2049 from a remote client; no local login is required.\nAC:H - Hitting the bug requires nfsd_file_cache_shutdown_net() to interleave with unhash plus delayed dispose; a remote client can populate the cache and trigger GC, shrinker, or fsnotify close, but cannot itself stop nfsd or destroy the server net namespace.\nPR:N - Typical nfsd deployments allow AUTH_SYS/AUTH_NULL with IP-based exports, so a remote peer that can reach the export self-asserts credentials with no cryptographic authentication and can populate the filecache via READ/WRITE.\nUI:N - Attacker-sent NFS operations drive the filecache side; no victim user action such as mounting a filesystem or opening a local file is required.\nS:U - The use-after-free or leak corrupts kernel nfsd_file/nfsd_net state within the host nfsd authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - Delayed dispose can call net_generic() and list_move on nfsd_net after per-net teardown frees it, a use-after-free of slab per-net data that enables reuse/spray and arbitrary kernel memory disclosure.\nI:H - The same freed nfsd_net is used for spin_lock and list_move_tail, a use-after-free write primitive that enables heap spraying, object corruption, and control-flow hijacking.\nA:H - Use-after-free of nfsd_net can oops or panic, and leaked nfsd_file objects permanently pin struct file/inode state so filesystem and netns teardown can hang, fully disrupting the NFS server host." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nfsd/filecache.c" ], "versions": [ { "version": "ffb402596147ac583f3464ff5c48feb9423e3838", "lessThan": "b15997b53b61c74fb4d083f7261d19f389ff854f", "status": "affected", "versionType": "git" }, { "version": "ffb402596147ac583f3464ff5c48feb9423e3838", "lessThan": "6d6b9f6a75c3767250e9c23ace4e384ab8f7843e", "status": "affected", "versionType": "git" }, { "version": "ffb402596147ac583f3464ff5c48feb9423e3838", "lessThan": "08af9593e2b472fd98c00faf1bf03bdbb7203477", "status": "affected", "versionType": "git" }, { "version": "ffb402596147ac583f3464ff5c48feb9423e3838", "lessThan": "40162cfea79b9510380decfdd1795b754dc9f972", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nfsd/filecache.c" ], "versions": [ { "version": "6.9", "status": "affected" }, { "version": "0", "lessThan": "6.9", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.111", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.51", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.12.111" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.18.51" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/b15997b53b61c74fb4d083f7261d19f389ff854f" }, { "url": "https://git.kernel.org/stable/c/6d6b9f6a75c3767250e9c23ace4e384ab8f7843e" }, { "url": "https://git.kernel.org/stable/c/08af9593e2b472fd98c00faf1bf03bdbb7203477" }, { "url": "https://git.kernel.org/stable/c/40162cfea79b9510380decfdd1795b754dc9f972" } ], "title": "nfsd: close shrinker/GC/fsnotify vs per-net shutdown race in filecache", "x_generator": { "engine": "bippy-1.2.0" } } } }