{"api_version":"1","generated_at":"2026-09-11T22:05:28+00:00","cve":"CVE-2026-89712","urls":{"html":"https://cve.report/CVE-2026-89712","api":"https://cve.report/api/cve/CVE-2026-89712.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-89712","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-89712"},"summary":{"title":"NFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock\n\nnfsd4_ssc_expire_umount() walks nn->nfsd_ssc_mount_list with\nlist_for_each_entry_safe(ni, tmp, ...).  For each expired entry it\nsets nsui_busy = true, drops nfsd_ssc_lock to run mntput() on the\nsource vfsmount, then reacquires the lock to list_del + kfree the\nentry and continue iterating via the macro's saved tmp pointer.\n\nThe nsui_busy flag protects the current ni from concurrent\nnfsd4_ssc_setup_dul() finders during the lock-drop window, but it\ndoes not pin tmp.  Another nfsd RPC thread that fails its source-\nserver mount and reaches nfsd4_ssc_cancel_dul() will, during that\nsame window, take nfsd_ssc_lock, list_del + kfree its own ssc_umount\nitem, and release the lock.  If that item is the saved tmp of the\nexpire walk, the next iteration dereferences a freed\nnfsd4_ssc_umount_item.\n\nRestart the walk from the head after the mntput() unlock window so\nno saved next pointer survives the lock-drop.  The list is bounded\nby the number of active inter-server source mounts (typically small)\nand the expire delayed-work runs periodically rather than per-IO,\nso the restart is cheap.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:58","updated_at":"2026-09-11 20:19:58"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/036c1b182f4da65363e79ec0ac276edc6b7296e5","name":"https://git.kernel.org/stable/c/036c1b182f4da65363e79ec0ac276edc6b7296e5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/7377fa964b8aaf47cb04e5efcc4c82d15e8c2ce9","name":"https://git.kernel.org/stable/c/7377fa964b8aaf47cb04e5efcc4c82d15e8c2ce9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/77de363d9a1c8cd35f20482782c612cda085791a","name":"https://git.kernel.org/stable/c/77de363d9a1c8cd35f20482782c612cda085791a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4ed8d2317aef21cc2a9e5a55d6b59860b4b151a8","name":"https://git.kernel.org/stable/c/4ed8d2317aef21cc2a9e5a55d6b59860b4b151a8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89712","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89712","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f4e44b393389c77958f7c58bf4415032b4cda15b 77de363d9a1c8cd35f20482782c612cda085791a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f4e44b393389c77958f7c58bf4415032b4cda15b 4ed8d2317aef21cc2a9e5a55d6b59860b4b151a8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f4e44b393389c77958f7c58bf4415032b4cda15b 7377fa964b8aaf47cb04e5efcc4c82d15e8c2ce9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f4e44b393389c77958f7c58bf4415032b4cda15b 036c1b182f4da65363e79ec0ac276edc6b7296e5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a4bc287943f5695209ff36bdc89f17b48d68fae7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.10.220 5.11 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.14","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.14 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.109 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.50 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.4 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/nfsd/nfs4state.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"77de363d9a1c8cd35f20482782c612cda085791a","status":"affected","version":"f4e44b393389c77958f7c58bf4415032b4cda15b","versionType":"git"},{"lessThan":"4ed8d2317aef21cc2a9e5a55d6b59860b4b151a8","status":"affected","version":"f4e44b393389c77958f7c58bf4415032b4cda15b","versionType":"git"},{"lessThan":"7377fa964b8aaf47cb04e5efcc4c82d15e8c2ce9","status":"affected","version":"f4e44b393389c77958f7c58bf4415032b4cda15b","versionType":"git"},{"lessThan":"036c1b182f4da65363e79ec0ac276edc6b7296e5","status":"affected","version":"f4e44b393389c77958f7c58bf4415032b4cda15b","versionType":"git"},{"status":"affected","version":"a4bc287943f5695209ff36bdc89f17b48d68fae7","versionType":"git"},{"lessThan":"5.11","status":"affected","version":"5.10.220","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/nfsd/nfs4state.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.14"},{"lessThan":"5.14","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.109","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.50","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.109","versionStartIncluding":"5.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.50","versionStartIncluding":"5.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.4","versionStartIncluding":"5.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"5.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.220","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock\n\nnfsd4_ssc_expire_umount() walks nn->nfsd_ssc_mount_list with\nlist_for_each_entry_safe(ni, tmp, ...).  For each expired entry it\nsets nsui_busy = true, drops nfsd_ssc_lock to run mntput() on the\nsource vfsmount, then reacquires the lock to list_del + kfree the\nentry and continue iterating via the macro's saved tmp pointer.\n\nThe nsui_busy flag protects the current ni from concurrent\nnfsd4_ssc_setup_dul() finders during the lock-drop window, but it\ndoes not pin tmp.  Another nfsd RPC thread that fails its source-\nserver mount and reaches nfsd4_ssc_cancel_dul() will, during that\nsame window, take nfsd_ssc_lock, list_del + kfree its own ssc_umount\nitem, and release the lock.  If that item is the saved tmp of the\nexpire walk, the next iteration dereferences a freed\nnfsd4_ssc_umount_item.\n\nRestart the walk from the head after the mntput() unlock window so\nno saved next pointer survives the lock-drop.  The list is bounded\nby the number of active inter-server source mounts (typically small)\nand the expire delayed-work runs periodically rather than per-IO,\nso the restart is cheap."}],"providerMetadata":{"dateUpdated":"2026-09-11T19:46:27.018Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/77de363d9a1c8cd35f20482782c612cda085791a"},{"url":"https://git.kernel.org/stable/c/4ed8d2317aef21cc2a9e5a55d6b59860b4b151a8"},{"url":"https://git.kernel.org/stable/c/7377fa964b8aaf47cb04e5efcc4c82d15e8c2ce9"},{"url":"https://git.kernel.org/stable/c/036c1b182f4da65363e79ec0ac276edc6b7296e5"}],"title":"NFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-89712","datePublished":"2026-09-11T19:46:27.018Z","dateReserved":"2026-09-11T19:38:34.751Z","dateUpdated":"2026-09-11T19:46:27.018Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:58","lastModifiedDate":"2026-09-11 20:19:58","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"89712","Ordinal":"1","Title":"NFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_loc","CVE":"CVE-2026-89712","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"89712","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock\n\nnfsd4_ssc_expire_umount() walks nn->nfsd_ssc_mount_list with\nlist_for_each_entry_safe(ni, tmp, ...).  For each expired entry it\nsets nsui_busy = true, drops nfsd_ssc_lock to run mntput() on the\nsource vfsmount, then reacquires the lock to list_del + kfree the\nentry and continue iterating via the macro's saved tmp pointer.\n\nThe nsui_busy flag protects the current ni from concurrent\nnfsd4_ssc_setup_dul() finders during the lock-drop window, but it\ndoes not pin tmp.  Another nfsd RPC thread that fails its source-\nserver mount and reaches nfsd4_ssc_cancel_dul() will, during that\nsame window, take nfsd_ssc_lock, list_del + kfree its own ssc_umount\nitem, and release the lock.  If that item is the saved tmp of the\nexpire walk, the next iteration dereferences a freed\nnfsd4_ssc_umount_item.\n\nRestart the walk from the head after the mntput() unlock window so\nno saved next pointer survives the lock-drop.  The list is bounded\nby the number of active inter-server source mounts (typically small)\nand the expire delayed-work runs periodically rather than per-IO,\nso the restart is cheap.","Type":"Description","Title":"NFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_loc"}]}}}