{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-50043", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-10-21T12:17:06.071Z", "datePublished": "2024-10-21T19:39:41.758Z", "dateUpdated": "2026-08-05T11:41:12.954Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:41:12.954Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix possible badness in FREE_STATEID\n\nWhen multiple FREE_STATEIDs are sent for the same delegation stateid,\nit can lead to a possible either use-after-free or counter refcount\nunderflow errors.\n\nIn nfsd4_free_stateid() under the client lock we find a delegation\nstateid, however the code drops the lock before calling nfs4_put_stid(),\nthat allows another FREE_STATE to find the stateid again. The first one\nwill proceed to then free the stateid which leads to either\nuse-after-free or decrementing already zeroed counter." } ], "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 - The vulnerable code is the NFSv4.1 FREE_STATEID compound operation in the in-kernel NFS server, driven entirely by RPC messages arriving from a remote client over TCP port 2049. No local access to the server is required.\nAC:L - The attacker controls both sides of the race — it creates the revoked delegation (by ignoring CB_RECALL until the laundromat revokes it) and then issues two concurrent FREE_STATEID compounds on separate session slots serviced by separate nfsd threads, retrying across arbitrarily many delegations. Concurrent stateid lookups that take transient references make the premature free reachable even without winning a tight window.\nPR:N - NFSv4.1 session establishment (EXCHANGE_ID/CREATE_SESSION) and AUTH_SYS access require no credential verification — the client simply asserts its own identity — so any host permitted to reach the export is effectively unauthenticated, consistent with prior kernel.org scoring of client-reachable nfsd state-handling flaws.\nUI:N - The entire sequence (obtain delegation, provoke recall, let it be revoked, send racing FREE_STATEIDs) is performed by the attacking client with no action by any server-side user or administrator.\nS:U - The corruption is confined to kernel memory within the NFS server's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The double put frees a `nfs4_delegation` slab object while live references remain, giving a use-after-free that is reallocatable with attacker-groomed content and read back through `sc_file`/`sc_client`/`sc_stateid`, enabling disclosure of arbitrary kernel memory.\nI:H - The second `nfs4_put_stid()` writes into the freed object (`refcount_dec_and_lock`), spinlocks on a `clp` pointer read from freed memory, and can indirectly call `s->sc_free(s)` — a function pointer at a fixed offset in a reclaimable non-RCU slab object — yielding a control-flow-hijack/arbitrary-write primitive.\nA:H - Even unexploited, the refcount underflow trips a refcount_t WARN/saturation and the use-after-free on the delegation object corrupts the deleg_slab freelist and the client's stateid IDR, reliably oopsing or panicking the NFS server host." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nfsd/nfs4state.c" ], "versions": [ { "version": "3f29cc82a84c23cfd12b903029dd26002ca825f5", "lessThan": "7ca9e472ce5c67daa3188a348ece8c02a0765039", "status": "affected", "versionType": "git" }, { "version": "3f29cc82a84c23cfd12b903029dd26002ca825f5", "lessThan": "c88c150a467fcb670a1608e2272beeee3e86df6e", "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/nfsd/nfs4state.c" ], "versions": [ { "version": "6.9", "status": "affected" }, { "version": "0", "lessThan": "6.9", "status": "unaffected", "versionType": "semver" }, { "version": "6.11.4", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12", "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": "6.9", "versionEndExcluding": "6.11.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.12" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/7ca9e472ce5c67daa3188a348ece8c02a0765039" }, { "url": "https://git.kernel.org/stable/c/c88c150a467fcb670a1608e2272beeee3e86df6e" } ], "title": "nfsd: fix possible badness in FREE_STATEID", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2024-50043", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-10-22T13:24:30.411615Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-10-22T13:28:43.975Z" } } ] } }