{"api_version":"1","generated_at":"2026-07-20T14:43:32+00:00","cve":"CVE-2026-64142","urls":{"html":"https://cve.report/CVE-2026-64142","api":"https://cve.report/api/cve/CVE-2026-64142.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64142","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64142"},"summary":{"title":"ksmbd: close durable scavenger races against m_fp_list lookups","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: close durable scavenger races against m_fp_list lookups\n\nksmbd_durable_scavenger() has two related races against any walker\nthat iterates f_ci->m_fp_list, including ksmbd_lookup_fd_inode()\n(used by ksmbd_vfs_rename) and the share-mode checks in\nfs/smb/server/smb_common.c.\n\n(1) fp->node list-head reuse.  Durable-preserved handles can remain\nlinked on f_ci->m_fp_list after session teardown so share-mode checks\nstill see them while the handle is reconnectable.  The scavenger\ncollected expired handles by adding fp->node to a local\nscavenger_list after removing them from the global durable idr.\nBecause fp->node is the same list_head used by m_fp_list,\nlist_add(&fp->node, &scavenger_list) overwrites the m_fp_list links\nand corrupts both lists.  CONFIG_DEBUG_LIST can report this on the\nshare-mode walk path.\n\n(2) Refcount race against m_fp_list walkers.  The scavenger qualifies\nan expired durable handle with atomic_read(&fp->refcount) > 1 and\nfp->conn under global_ft.lock, removes fp from global_ft, then drops\nglobal_ft.lock before unlinking fp from m_fp_list and freeing it.\nDuring that gap fp is still linked on m_fp_list with f_state ==\nFP_INITED.  ksmbd_lookup_fd_inode() under m_lock read calls\nksmbd_fp_get() (atomic_inc_not_zero on refcount that is still 1) and\ntakes a live reference; the scavenger then unlinks and frees fp\nwhile the holder owns a reference, leading to UAF on the holder's\nsubsequent ksmbd_fd_put() and on any field reads performed by a\nconcurrent share-mode walker that iterates m_fp_list without taking\nksmbd_fp_get() (smb_check_perm_dleases-like paths).\n\nFix both:\n\n  * Stop reusing fp->node as a scavenger-private list node.  Remove\n    one expired handle from global_ft under global_ft.lock, take an\n    explicit transient reference, drop the lock, unlink fp->node\n    from m_fp_list under f_ci->m_lock, then drop both the durable\n    lifetime and transient references with atomic_sub_and_test(2,\n    &fp->refcount).  If the scavenger is the last putter the close\n    runs there; otherwise an in-flight holder that already raced\n    through the m_fp_list lookup owns the final close via its\n    ksmbd_fd_put() path.  The one-at-a-time disposal can rescan the\n    durable idr when multiple handles expire in the same pass, but\n    durable scavenging is a background expiration path and the final\n    full scan recomputes min_timeout before the next wait.\n\n  * Clear fp->persistent_id inside __ksmbd_remove_durable_fd() right\n    after idr_remove(), so a delayed final close from a holder that\n    snatched fp does not re-issue idr_remove() on a persistent id\n    that idr_alloc_cyclic() in ksmbd_open_durable_fd() may have\n    already handed out to a brand-new durable handle.\n\n  * Bypass the per-conn open_files_count decrement in\n    __put_fd_final() when fp is detached from any session table\n    (fp->conn cleared by session_fd_check() at durable preserve --\n    paired with the volatile_id clear at unpublish, so checking\n    fp->conn alone is sufficient).  The walker that owns the final\n    close runs from an unrelated work->conn whose\n    stats.open_files_count never tracked this durable fp; without\n    this guard the holder would underflow that unrelated counter.\n\nThe two races are folded into one patch because patch (1) alone\ncleans up the corrupted list but leaves a deterministic UAF window\nfor m_fp_list walkers that the transient-reference and\npersistent_id discipline in (2) close; bisecting onto an\nintermediate state would land on a UAF that pre-patch chaos merely\nmade less reproducible.\n\nValidation:\n  * CONFIG_DEBUG_LIST coverage for the list_head reuse path.\n  * KASAN-enabled direct SMB2 durable-handle coverage that exercised\n    ksmbd_durable_scavenger() and non-NULL ksmbd_lookup_fd_inode()\n    returns while durable handles expired under concurrent rename\n    lookups, with no KASAN, UAF, list-corruption, ODEBUG, or WARNING\n    reports.\n---truncated---","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:17:56","updated_at":"2026-07-19 16:17:56"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/5da69a65b282d2276de22e5194ba0f88c836170c","name":"https://git.kernel.org/stable/c/5da69a65b282d2276de22e5194ba0f88c836170c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bf736184d063da1a552ffeff0481813599a182cc","name":"https://git.kernel.org/stable/c/bf736184d063da1a552ffeff0481813599a182cc","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3a436932eb397e909d0607d76a8325abd9d85a35","name":"https://git.kernel.org/stable/c/3a436932eb397e909d0607d76a8325abd9d85a35","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1f8f3246d55f89350a1a67bdf3744b7241048e4e","name":"https://git.kernel.org/stable/c/1f8f3246d55f89350a1a67bdf3744b7241048e4e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/95f072ef934ca00711d510676b8792cbf59a5aae","name":"https://git.kernel.org/stable/c/95f072ef934ca00711d510676b8792cbf59a5aae","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64142","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64142","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7f0cb478703cbeaddfe5c9101c5c73cd975d1073 3a436932eb397e909d0607d76a8325abd9d85a35 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d484d621d40f4a8b8959008802d79bef3609641b 95f072ef934ca00711d510676b8792cbf59a5aae git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d484d621d40f4a8b8959008802d79bef3609641b 5da69a65b282d2276de22e5194ba0f88c836170c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d484d621d40f4a8b8959008802d79bef3609641b 1f8f3246d55f89350a1a67bdf3744b7241048e4e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d484d621d40f4a8b8959008802d79bef3609641b bf736184d063da1a552ffeff0481813599a182cc git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.11","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.11 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.92 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.34 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.11 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * 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/smb/server/vfs_cache.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"3a436932eb397e909d0607d76a8325abd9d85a35","status":"affected","version":"7f0cb478703cbeaddfe5c9101c5c73cd975d1073","versionType":"git"},{"lessThan":"95f072ef934ca00711d510676b8792cbf59a5aae","status":"affected","version":"d484d621d40f4a8b8959008802d79bef3609641b","versionType":"git"},{"lessThan":"5da69a65b282d2276de22e5194ba0f88c836170c","status":"affected","version":"d484d621d40f4a8b8959008802d79bef3609641b","versionType":"git"},{"lessThan":"1f8f3246d55f89350a1a67bdf3744b7241048e4e","status":"affected","version":"d484d621d40f4a8b8959008802d79bef3609641b","versionType":"git"},{"lessThan":"bf736184d063da1a552ffeff0481813599a182cc","status":"affected","version":"d484d621d40f4a8b8959008802d79bef3609641b","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/smb/server/vfs_cache.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.11"},{"lessThan":"6.11","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.92","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.34","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.11","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.92","versionStartIncluding":"6.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.34","versionStartIncluding":"6.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.11","versionStartIncluding":"6.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"6.11","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: close durable scavenger races against m_fp_list lookups\n\nksmbd_durable_scavenger() has two related races against any walker\nthat iterates f_ci->m_fp_list, including ksmbd_lookup_fd_inode()\n(used by ksmbd_vfs_rename) and the share-mode checks in\nfs/smb/server/smb_common.c.\n\n(1) fp->node list-head reuse.  Durable-preserved handles can remain\nlinked on f_ci->m_fp_list after session teardown so share-mode checks\nstill see them while the handle is reconnectable.  The scavenger\ncollected expired handles by adding fp->node to a local\nscavenger_list after removing them from the global durable idr.\nBecause fp->node is the same list_head used by m_fp_list,\nlist_add(&fp->node, &scavenger_list) overwrites the m_fp_list links\nand corrupts both lists.  CONFIG_DEBUG_LIST can report this on the\nshare-mode walk path.\n\n(2) Refcount race against m_fp_list walkers.  The scavenger qualifies\nan expired durable handle with atomic_read(&fp->refcount) > 1 and\nfp->conn under global_ft.lock, removes fp from global_ft, then drops\nglobal_ft.lock before unlinking fp from m_fp_list and freeing it.\nDuring that gap fp is still linked on m_fp_list with f_state ==\nFP_INITED.  ksmbd_lookup_fd_inode() under m_lock read calls\nksmbd_fp_get() (atomic_inc_not_zero on refcount that is still 1) and\ntakes a live reference; the scavenger then unlinks and frees fp\nwhile the holder owns a reference, leading to UAF on the holder's\nsubsequent ksmbd_fd_put() and on any field reads performed by a\nconcurrent share-mode walker that iterates m_fp_list without taking\nksmbd_fp_get() (smb_check_perm_dleases-like paths).\n\nFix both:\n\n  * Stop reusing fp->node as a scavenger-private list node.  Remove\n    one expired handle from global_ft under global_ft.lock, take an\n    explicit transient reference, drop the lock, unlink fp->node\n    from m_fp_list under f_ci->m_lock, then drop both the durable\n    lifetime and transient references with atomic_sub_and_test(2,\n    &fp->refcount).  If the scavenger is the last putter the close\n    runs there; otherwise an in-flight holder that already raced\n    through the m_fp_list lookup owns the final close via its\n    ksmbd_fd_put() path.  The one-at-a-time disposal can rescan the\n    durable idr when multiple handles expire in the same pass, but\n    durable scavenging is a background expiration path and the final\n    full scan recomputes min_timeout before the next wait.\n\n  * Clear fp->persistent_id inside __ksmbd_remove_durable_fd() right\n    after idr_remove(), so a delayed final close from a holder that\n    snatched fp does not re-issue idr_remove() on a persistent id\n    that idr_alloc_cyclic() in ksmbd_open_durable_fd() may have\n    already handed out to a brand-new durable handle.\n\n  * Bypass the per-conn open_files_count decrement in\n    __put_fd_final() when fp is detached from any session table\n    (fp->conn cleared by session_fd_check() at durable preserve --\n    paired with the volatile_id clear at unpublish, so checking\n    fp->conn alone is sufficient).  The walker that owns the final\n    close runs from an unrelated work->conn whose\n    stats.open_files_count never tracked this durable fp; without\n    this guard the holder would underflow that unrelated counter.\n\nThe two races are folded into one patch because patch (1) alone\ncleans up the corrupted list but leaves a deterministic UAF window\nfor m_fp_list walkers that the transient-reference and\npersistent_id discipline in (2) close; bisecting onto an\nintermediate state would land on a UAF that pre-patch chaos merely\nmade less reproducible.\n\nValidation:\n  * CONFIG_DEBUG_LIST coverage for the list_head reuse path.\n  * KASAN-enabled direct SMB2 durable-handle coverage that exercised\n    ksmbd_durable_scavenger() and non-NULL ksmbd_lookup_fd_inode()\n    returns while durable handles expired under concurrent rename\n    lookups, with no KASAN, UAF, list-corruption, ODEBUG, or WARNING\n    reports.\n---truncated---"}],"providerMetadata":{"dateUpdated":"2026-07-19T15:40:34.605Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/3a436932eb397e909d0607d76a8325abd9d85a35"},{"url":"https://git.kernel.org/stable/c/95f072ef934ca00711d510676b8792cbf59a5aae"},{"url":"https://git.kernel.org/stable/c/5da69a65b282d2276de22e5194ba0f88c836170c"},{"url":"https://git.kernel.org/stable/c/1f8f3246d55f89350a1a67bdf3744b7241048e4e"},{"url":"https://git.kernel.org/stable/c/bf736184d063da1a552ffeff0481813599a182cc"}],"title":"ksmbd: close durable scavenger races against m_fp_list lookups","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64142","datePublished":"2026-07-19T15:40:34.605Z","dateReserved":"2026-07-19T07:54:57.037Z","dateUpdated":"2026-07-19T15:40:34.605Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:17:56","lastModifiedDate":"2026-07-19 16:17:56","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64142","Ordinal":"1","Title":"ksmbd: close durable scavenger races against m_fp_list lookups","CVE":"CVE-2026-64142","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64142","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: close durable scavenger races against m_fp_list lookups\n\nksmbd_durable_scavenger() has two related races against any walker\nthat iterates f_ci->m_fp_list, including ksmbd_lookup_fd_inode()\n(used by ksmbd_vfs_rename) and the share-mode checks in\nfs/smb/server/smb_common.c.\n\n(1) fp->node list-head reuse.  Durable-preserved handles can remain\nlinked on f_ci->m_fp_list after session teardown so share-mode checks\nstill see them while the handle is reconnectable.  The scavenger\ncollected expired handles by adding fp->node to a local\nscavenger_list after removing them from the global durable idr.\nBecause fp->node is the same list_head used by m_fp_list,\nlist_add(&fp->node, &scavenger_list) overwrites the m_fp_list links\nand corrupts both lists.  CONFIG_DEBUG_LIST can report this on the\nshare-mode walk path.\n\n(2) Refcount race against m_fp_list walkers.  The scavenger qualifies\nan expired durable handle with atomic_read(&fp->refcount) > 1 and\nfp->conn under global_ft.lock, removes fp from global_ft, then drops\nglobal_ft.lock before unlinking fp from m_fp_list and freeing it.\nDuring that gap fp is still linked on m_fp_list with f_state ==\nFP_INITED.  ksmbd_lookup_fd_inode() under m_lock read calls\nksmbd_fp_get() (atomic_inc_not_zero on refcount that is still 1) and\ntakes a live reference; the scavenger then unlinks and frees fp\nwhile the holder owns a reference, leading to UAF on the holder's\nsubsequent ksmbd_fd_put() and on any field reads performed by a\nconcurrent share-mode walker that iterates m_fp_list without taking\nksmbd_fp_get() (smb_check_perm_dleases-like paths).\n\nFix both:\n\n  * Stop reusing fp->node as a scavenger-private list node.  Remove\n    one expired handle from global_ft under global_ft.lock, take an\n    explicit transient reference, drop the lock, unlink fp->node\n    from m_fp_list under f_ci->m_lock, then drop both the durable\n    lifetime and transient references with atomic_sub_and_test(2,\n    &fp->refcount).  If the scavenger is the last putter the close\n    runs there; otherwise an in-flight holder that already raced\n    through the m_fp_list lookup owns the final close via its\n    ksmbd_fd_put() path.  The one-at-a-time disposal can rescan the\n    durable idr when multiple handles expire in the same pass, but\n    durable scavenging is a background expiration path and the final\n    full scan recomputes min_timeout before the next wait.\n\n  * Clear fp->persistent_id inside __ksmbd_remove_durable_fd() right\n    after idr_remove(), so a delayed final close from a holder that\n    snatched fp does not re-issue idr_remove() on a persistent id\n    that idr_alloc_cyclic() in ksmbd_open_durable_fd() may have\n    already handed out to a brand-new durable handle.\n\n  * Bypass the per-conn open_files_count decrement in\n    __put_fd_final() when fp is detached from any session table\n    (fp->conn cleared by session_fd_check() at durable preserve --\n    paired with the volatile_id clear at unpublish, so checking\n    fp->conn alone is sufficient).  The walker that owns the final\n    close runs from an unrelated work->conn whose\n    stats.open_files_count never tracked this durable fp; without\n    this guard the holder would underflow that unrelated counter.\n\nThe two races are folded into one patch because patch (1) alone\ncleans up the corrupted list but leaves a deterministic UAF window\nfor m_fp_list walkers that the transient-reference and\npersistent_id discipline in (2) close; bisecting onto an\nintermediate state would land on a UAF that pre-patch chaos merely\nmade less reproducible.\n\nValidation:\n  * CONFIG_DEBUG_LIST coverage for the list_head reuse path.\n  * KASAN-enabled direct SMB2 durable-handle coverage that exercised\n    ksmbd_durable_scavenger() and non-NULL ksmbd_lookup_fd_inode()\n    returns while durable handles expired under concurrent rename\n    lookups, with no KASAN, UAF, list-corruption, ODEBUG, or WARNING\n    reports.\n---truncated---","Type":"Description","Title":"ksmbd: close durable scavenger races against m_fp_list lookups"}]}}}