{"schema":"threatline.record/2","record":{"id":"CVE-2026-93221","aliases":[],"summary":"nfsd: convert nfsd_net boolean flags to unsigned long flags word","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: convert nfsd_net boolean flags to unsigned long flags word\n\nnfsd_net contains several boolean fields that are accessed from\nconcurrent contexts without serialization.  In particular,\nnfsd4_end_grace() guards its drain path with a plain bool:\n\n    if (nn->grace_ended)\n            return;\n    nn->grace_ended = true;\n\nThe read and the write are independent, and nothing in struct\nnfsd_net serializes them.  At least two contexts can reach this\ncode with no lock held:\n\n    laundromat path\n      laundry_wq kworker\n        nfs4_laundromat()\n          nfsd4_end_grace()\n\n    RECLAIM_COMPLETE path\n      nfsd compound kthread\n        nfsd4_reclaim_complete()\n          inc_reclaim_complete()\n            nfsd4_end_grace()\n\nBoth callers can observe grace_ended == false on different CPUs,\nboth store true, and both proceed into nfsd4_record_grace_done(),\nwhich invokes the active client_tracking_ops->grace_done callback.\nFor tracking ops that drain reclaim_str_hashtbl (legacy_tracking_ops\nvia nfsd4_recdir_purge_old, and the cld v1+ ops via\nnfsd4_cld_grace_done), grace_done calls nfs4_release_reclaim(),\nwhich walks every bucket of reclaim_str_hashtbl with no lock and\ncalls nfs4_remove_reclaim_record() (list_del + kfree) on each\nentry.  Two concurrent walkers corrupt the list and double-free\nevery nfs4_client_reclaim.  A concurrent nfsd4_find_reclaim_client()\niterating the same bucket reads through freed memory.\n\nA third call site exists in nfs4_state_start_net() on the\nskip_grace startup path, but it runs under nfsd_mutex before any\nclient has connected and before the laundromat's first delayed\nwork fires, so it cannot race with the two callers above.\n\nReplace the scattered boolean fields in nfsd_net with a single\nunsigned long flags word and an enum nfsd_net_flag for the bit\npositions.  The grace_ended race is fixed by using\ntest_and_set_bit(), which is atomic on all architectures.  The\nremaining flags (grace_end_forced, in_grace, somebody_reclaimed,\ntrack_reclaim_completes, nfsd_net_up, lockd_up) are converted to\nuse test_bit/set_bit/clear_bit for consistency.  This avoids\nsub-word cmpxchg issues on architectures like Hexagon that only\nsupport word-sized atomic operations.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93221","source_modified_at":"2026-10-21T12:52:22.888Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"362063a595be959bc08f4163e6405a0266740091","lessThan":"94b450977c60261903c945419d2df4a464de60c4","status":"affected","versionType":"git"},{"version":"362063a595be959bc08f4163e6405a0266740091","lessThan":"faac245ca739b66e96fb7bb43e21df537239a4e5","status":"affected","versionType":"git"},{"version":"362063a595be959bc08f4163e6405a0266740091","lessThan":"40bab0da844c142431a6b1cc21b4cf53491dac44","status":"affected","versionType":"git"},{"version":"362063a595be959bc08f4163e6405a0266740091","lessThan":"df5922fe09a8131c793ffa86adf204999b0470f8","status":"affected","versionType":"git"},{"version":"362063a595be959bc08f4163e6405a0266740091","lessThan":"11a5fe42e1811f793e04ef885b639ea7668f439d","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93221","source_modified_at":"2026-10-21T12:52:22.888Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"5.2","status":"affected"},{"version":"0","lessThan":"5.2","status":"unaffected","versionType":"semver"},{"version":"6.6.160","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.114","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.57","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"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93221","source_modified_at":"2026-10-21T12:52:22.888Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"94b450977c60261903c945419d2df4a464de60c4","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93221","source_modified_at":"2026-10-21T12:52:22.888Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"40bab0da844c142431a6b1cc21b4cf53491dac44","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93221","source_modified_at":"2026-10-21T12:52:22.888Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"11a5fe42e1811f793e04ef885b639ea7668f439d","basis":"first unaffected version stated in the CVE record"}],"cvss":8.1,"severity":"High","kev":{"listed":false},"epss":{"probability":0.00422,"percentile":0.35504,"score_date":"2026-10-23"},"published_at":"2026-09-24T15:10:44.598Z","modified_at":"2026-10-21T12:52:22.888Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-93221","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-21T12:52:22.888Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-93221","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/94b450977c60261903c945419d2df4a464de60c4"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/faac245ca739b66e96fb7bb43e21df537239a4e5"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/40bab0da844c142431a6b1cc21b4cf53491dac44"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/df5922fe09a8131c793ffa86adf204999b0470f8"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/11a5fe42e1811f793e04ef885b639ea7668f439d"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-21T12:52:22.888Z","content_hash":"4135da05fd7d57fb584080ccfcfaa3b897ff79a09ea244f92569028a44736490"}}