{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89485", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.712Z", "datePublished": "2026-09-11T19:43:39.403Z", "dateUpdated": "2026-10-19T08:47:35.868Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:47:35.868Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlockd: pin next file across nlm_inspect_file lock-drop\n\nnlm_traverse_files() pins the current file with f_count++ across\na mutex_unlock for nlm_inspect_file(), but nothing pins the saved\nnext pointer. A concurrent nlm_release_file() can kfree the next\nfile during the unlock window, and the iterator dereferences freed\nmemory on the next loop step.\n\nPin both current and next before the lock-drop. Advance by\nswapping the pinned cursors at the end of each iteration so next\nis always held alive across the unlock.\n\nAlways call nlm_file_release() after dropping the iteration pin,\nregardless of whether the file matched the predicate. Use\nnlm_file_inuse(), which does a live walk of the inode lock list,\nrather than the cached f_locks field, so skipped files that never\nran nlm_inspect_file() are evaluated correctly.\n\nBecause every file in a hash bucket is now pinned and released,\nfiles skipped by the is_failover_file predicate that have no\nlocks, blocks, shares, or external references are deleted during\ntraversal. The old code never evaluated skipped files for\ncleanup. The new behavior is intentional: such files are stale\nand should not persist in the table." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - lockd is the in-kernel NLM RPC server on TCP/UDP, reached by remote NFSv3 clients. nlm_traverse_files() runs on NLMPROC_FREE_ALL, and nlm_release_file() runs from LOCK/UNLOCK/TEST and from rpciod NLM_GRANTED_MSG completion, so the UAF is triggered by network NLM traffic.\nAC:L - A remote NFS client can populate nlm_files via LOCK, send FREE_ALL to drop nlm_file_mutex inside nlm_traverse_files(), and concurrently complete in-flight GRANTED_MSG callbacks so rpciod's nlmsvc_grant_release() calls nlm_release_file() on the unpinned next object; the attacker drives both sides of the race.\nPR:N - lockd_authenticate() accepts RPC_AUTH_NULL and RPC_AUTH_UNIX. FREE_ALL is not a privileged-port callback, and nlm_fopen() opens files with NFSD_MAY_BYPASS_GSS|NFSD_MAY_NLM, so no host account or capability is required.\nUI:N - Exploitation uses only attacker-sent NLM RPCs (LOCK/FREE_ALL and grant-callback completion); no victim user or administrator action is required.\nS:U - The use-after-free is in the host kernel's lockd file table and impacts that same kernel; it does not cross a VM, IOMMU, or other security-authority boundary.\nC:H - The iterator dereferences a kfree'd struct nlm_file (list pointers, f_file[], f_count). This UAF lets an attacker reuse the slab object and obtain a kernel read primitive, so confidentiality impact is high.\nI:H - The same nlm_file UAF is a kernel heap free of list nodes, mutex state, and struct file pointers, which can be sprayed for an arbitrary write and control-flow hijack, so integrity impact is high.\nA:H - Walking the freed nlm_file in nlm_traverse_files() causes a kernel oops/panic (KASAN slab-use-after-free), so availability impact is high." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/lockd/svcsubs.c" ], "versions": [ { "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171", "lessThan": "e3c413f789eaf0170275c7eba523ead73d963f30", "status": "affected", "versionType": "git" }, { "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171", "lessThan": "08a455f87b14c7ff22ae3fdadda62a796a3a5572", "status": "affected", "versionType": "git" }, { "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171", "lessThan": "550c19222c7132c888e23c9d89079ba1c9bc4cca", "status": "affected", "versionType": "git" }, { "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171", "lessThan": "350087f231c11efcd288c310707c40eab63ca583", "status": "affected", "versionType": "git" }, { "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171", "lessThan": "c24bdb7df2f34bdc38ca8a73796f5acb40f1830c", "status": "affected", "versionType": "git" }, { "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171", "lessThan": "41f0a6d31615fcae261bf28a0aa50050dc93a401", "status": "affected", "versionType": "git" }, { "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171", "lessThan": "e999a88133654c6dfc68487fb49da5f20dfa2d4f", "status": "affected", "versionType": "git" }, { "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171", "lessThan": "526c49cff3f72c3ec74752016380c7567040581b", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/lockd/svcsubs.c" ], "versions": [ { "version": "2.6.18", "status": "affected" }, { "version": "0", "lessThan": "2.6.18", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.270", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "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" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.18", "versionEndExcluding": "5.10.270" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.18", "versionEndExcluding": "5.15.221" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.18", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.18", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.18", "versionEndExcluding": "6.12.109" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.18", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.18", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.18", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/e3c413f789eaf0170275c7eba523ead73d963f30" }, { "url": "https://git.kernel.org/stable/c/08a455f87b14c7ff22ae3fdadda62a796a3a5572" }, { "url": "https://git.kernel.org/stable/c/550c19222c7132c888e23c9d89079ba1c9bc4cca" }, { "url": "https://git.kernel.org/stable/c/350087f231c11efcd288c310707c40eab63ca583" }, { "url": "https://git.kernel.org/stable/c/c24bdb7df2f34bdc38ca8a73796f5acb40f1830c" }, { "url": "https://git.kernel.org/stable/c/41f0a6d31615fcae261bf28a0aa50050dc93a401" }, { "url": "https://git.kernel.org/stable/c/e999a88133654c6dfc68487fb49da5f20dfa2d4f" }, { "url": "https://git.kernel.org/stable/c/526c49cff3f72c3ec74752016380c7567040581b" } ], "title": "lockd: pin next file across nlm_inspect_file lock-drop", "x_generator": { "engine": "bippy-1.2.0" } } } }