{"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":"2026-09-21T13:14:42.944Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-21T13:14:42.944Z"},"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-rc1","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-rc1"}]}]}],"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"}}}}