{"id":"CVE-2026-89667","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-89667","summary":"nfsd: close shrinker/GC/fsnotify vs per-net shutdown race in filecache","details":"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.","published":"2026-09-11T19:45:53.609Z","modified":"2026-09-14T03:45:38.757886194Z","cvss":{"score":8.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.18.51"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/08af9593e2b472fd98c00faf1bf03bdbb7203477"},{"type":"WEB","url":"https://git.kernel.org/stable/c/40162cfea79b9510380decfdd1795b754dc9f972"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6d6b9f6a75c3767250e9c23ace4e384ab8f7843e"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89667.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89667"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-14T03:45:38.757886194Z"}}