{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-64142", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-64142", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-07-19T15:40:34.605Z", "updatedAt": "2026-08-05T12:39:42.662Z", "importedAt": "2026-10-24T01:58:25.636Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "ksmbd: close durable scavenger races against m_fp_list lookups", "summary": "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---", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "7f0cb478703cbeaddfe5c9101c5c73cd975d1073", "status": "affected", "versionType": "git", "lessThan": "3a436932eb397e909d0607d76a8325abd9d85a35" }, { "version": "d484d621d40f4a8b8959008802d79bef3609641b", "status": "affected", "versionType": "git", "lessThan": "95f072ef934ca00711d510676b8792cbf59a5aae" }, { "version": "d484d621d40f4a8b8959008802d79bef3609641b", "status": "affected", "versionType": "git", "lessThan": "5da69a65b282d2276de22e5194ba0f88c836170c" }, { "version": "d484d621d40f4a8b8959008802d79bef3609641b", "status": "affected", "versionType": "git", "lessThan": "1f8f3246d55f89350a1a67bdf3744b7241048e4e" }, { "version": "d484d621d40f4a8b8959008802d79bef3609641b", "status": "affected", "versionType": "git", "lessThan": "bf736184d063da1a552ffeff0481813599a182cc" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "6.11", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "6.11" }, { "version": "6.12.92", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.34", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.0.11", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.0.*" }, { "version": "7.1", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }