{"id":"CVE-2026-93212","state":"PUBLISHED","title":"nfsd: guard nfsd_serv deref in nfsd_file_net_dispose","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: guard nfsd_serv deref in nfsd_file_net_dispose\n\nnfsd_file_net_dispose() is the consumer side of l->freeme: the nfsd\nservice thread loop calls it to drain entries that the filecache\ngarbage collector and shrinker append via\nnfsd_file_dispose_list_delayed().  During per-net teardown,\nnn->nfsd_serv is cleared before the filecache laundrette is shut\ndown, so the service thread can still run a dispose pass that finds\nmore than eight entries on l->freeme and dereferences a NULL\nsvc_serv:\n\n    nfsd service thread loop\n      nfsd_file_net_dispose(nn)\n        if (!list_empty(&l->freeme)) {\n            ...\n            svc_wake_up(nn->nfsd_serv);   /* nn->nfsd_serv == NULL */\n        }\n\nThe sibling helper nfsd_file_dispose_list_delayed() already documents\nthis ordering and caches nn->nfsd_serv into a local before testing it\nfor NULL.  nfsd_file_net_dispose() was introduced with the same raw\nsvc_wake_up(nn->nfsd_serv) call and never picked up the guard.\n\nFix by loading nn->nfsd_serv into a local svc_serv pointer and only\ncalling svc_wake_up() when it is non-NULL, matching the pattern in\nnfsd_file_dispose_list_delayed().","publishedAt":"2026-09-24T15:10:35.280Z","updatedAt":"2026-10-19T09:07:24.291Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ffb402596147ac583f3464ff5c48feb9423e3838","status":"affected","lessThan":"f4776c1c4b38fbc459420321c8ece87d0f7f95fb","versionType":"git"},{"version":"ffb402596147ac583f3464ff5c48feb9423e3838","status":"affected","lessThan":"59baf45a06435194005fc5fa9a42d89f77a30432","versionType":"git"},{"version":"ffb402596147ac583f3464ff5c48feb9423e3838","status":"affected","lessThan":"766170b4fd2daaf5c4d6735560101474e18edab6","versionType":"git"},{"version":"ffb402596147ac583f3464ff5c48feb9423e3838","status":"affected","lessThan":"9f1ddfc8cb9076592401a611eb3a44d36186d014","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/filecache.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.9","versionType":"semver"},{"version":"6.12.109","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.50","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/filecache.c"]}],"references":["https://git.kernel.org/stable/c/f4776c1c4b38fbc459420321c8ece87d0f7f95fb","https://git.kernel.org/stable/c/59baf45a06435194005fc5fa9a42d89f77a30432","https://git.kernel.org/stable/c/766170b4fd2daaf5c4d6735560101474e18edab6","https://git.kernel.org/stable/c/9f1ddfc8cb9076592401a611eb3a44d36186d014"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/93xxx/CVE-2026-93212.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-93212","state":"PUBLISHED","datePublished":"2026-09-24T15:10:35.280Z","dateUpdated":"2026-10-19T09:07:24.291Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-17T16:02:15.093Z"},"containers":{"cna":{"title":"nfsd: guard nfsd_serv deref in nfsd_file_net_dispose","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: guard nfsd_serv deref in nfsd_file_net_dispose\n\nnfsd_file_net_dispose() is the consumer side of l->freeme: the nfsd\nservice thread loop calls it to drain entries that the filecache\ngarbage collector and shrinker append via\nnfsd_file_dispose_list_delayed().  During per-net teardown,\nnn->nfsd_serv is cleared before the filecache laundrette is shut\ndown, so the service thread can still run a dispose pass that finds\nmore than eight entries on l->freeme and dereferences a NULL\nsvc_serv:\n\n    nfsd service thread loop\n      nfsd_file_net_dispose(nn)\n        if (!list_empty(&l->freeme)) {\n            ...\n            svc_wake_up(nn->nfsd_serv);   /* nn->nfsd_serv == NULL */\n        }\n\nThe sibling helper nfsd_file_dispose_list_delayed() already documents\nthis ordering and caches nn->nfsd_serv into a local before testing it\nfor NULL.  nfsd_file_net_dispose() was introduced with the same raw\nsvc_wake_up(nn->nfsd_serv) call and never picked up the guard.\n\nFix by loading nn->nfsd_serv into a local svc_serv pointer and only\ncalling svc_wake_up() when it is non-NULL, matching the pattern in\nnfsd_file_dispose_list_delayed()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ffb402596147ac583f3464ff5c48feb9423e3838","status":"affected","lessThan":"f4776c1c4b38fbc459420321c8ece87d0f7f95fb","versionType":"git"},{"version":"ffb402596147ac583f3464ff5c48feb9423e3838","status":"affected","lessThan":"59baf45a06435194005fc5fa9a42d89f77a30432","versionType":"git"},{"version":"ffb402596147ac583f3464ff5c48feb9423e3838","status":"affected","lessThan":"766170b4fd2daaf5c4d6735560101474e18edab6","versionType":"git"},{"version":"ffb402596147ac583f3464ff5c48feb9423e3838","status":"affected","lessThan":"9f1ddfc8cb9076592401a611eb3a44d36186d014","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/filecache.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.9","versionType":"semver"},{"version":"6.12.109","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.50","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/filecache.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/f4776c1c4b38fbc459420321c8ece87d0f7f95fb"},{"url":"https://git.kernel.org/stable/c/59baf45a06435194005fc5fa9a42d89f77a30432"},{"url":"https://git.kernel.org/stable/c/766170b4fd2daaf5c4d6735560101474e18edab6"},{"url":"https://git.kernel.org/stable/c/9f1ddfc8cb9076592401a611eb3a44d36186d014"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:07:24.291Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.12.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.18.50"},{"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"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}