{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-90037", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.782Z", "datePublished": "2026-09-16T10:33:36.673Z", "dateUpdated": "2026-10-30T12:33:53.924Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:33:53.924Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during close_lru reaping\n\nAn nfs4_openowner left on nn->close_lru after its final CLOSE keeps\nits last closed stateid in oo_last_closed_stid, holding only a raw\npointer to its nfs4_client. The laundromat reaps timed-out entries,\ndrops nn->client_lock, and calls nfs4_put_stid(), which dereferences\nthe client through cl_lock. Nothing pins the client across that\nwindow, so a concurrent force_expire_client() can free it and\nnfs4_put_stid() reads freed memory. __destroy_client() hits the same\nrace, walking clp->cl_openowners without cl_lock.\n\nPin the client with cl_rpc_users before dropping client_lock, and\nskip clients already expiring. __destroy_client() then cleans up its\nown close_lru entries through release_last_closed_stateid(), so\nteardown no longer races the laundromat." } ], "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 - nfsd is the in-kernel NFS server. A remote NFSv4.0 client reaches the UAF over TCP/UDP 2049: CLOSE places the openowner on nn->close_lru, and SETCLIENTID_CONFIRM (ALLOWED_WITHOUT_FH) calls expire_client() while nfs4_laundromat() drops client_lock and nfs4_put_stid() uses the unpinned nfs4_client.\nAC:L - The attacker drives both sides: OPEN/CLOSE compounds fill close_lru so the laundromat drops client_lock once per nfs4_put_stid(), and concurrent SETCLIENTID_CONFIRM with matching AUTH_SYS creds replaces the client via expire_client(). FATTR4_LEASE_TIME times the window; flooding close_lru widens it; the race is retryable.\nPR:N - Typical nfsd deployments use AUTH_SYS/AUTH_NULL, so RPC uids are self-asserted. SETCLIENTID and SETCLIENTID_CONFIRM are ALLOWED_WITHOUT_FH; any host allowed by the export can OPEN/CLOSE and replace the client with no local account or capability on the NFS server.\nUI:N - The attacker issues the NFSv4.0 compounds (SETCLIENTID, OPEN, CLOSE, RENEW, SETCLIENTID_CONFIRM) itself. No administrator or other user on the victim server must mount a filesystem, write nfsdfs ctl, or otherwise interact.\nS:U - The use-after-free is of the nfsd nfs4_client object (client_slab) in the NFS server kernel. Impact stays in that kernel security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - After free_client() kmem_cache_free()s the nfs4_client, nfs4_put_stid() still reads cl_lock and cl_stateids. Reclaiming the mergeable client_slab object via further SETCLIENTID discloses kernel heap; a UAF is C:H.\nI:H - nfs4_put_stid() then takes cl_lock and idr_remove()s from cl_stateids on the freed nfs4_client, a slab UAF write concurrent with __destroy_client(). Heap reuse enables arbitrary write and control-flow hijack; a UAF is I:H.\nA:H - Use-after-free of nfs4_client in nfs4_put_stid() (spin_lock of freed cl_lock) oopses or panics the nfsd laundromat worker even without a full exploit, denying service of 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": "217526e7ecc9f6f243e976772e81eab7ab986a4c", "lessThan": "1d721729762a413015864b2a56d7fb86fb8efa9f", "status": "affected", "versionType": "git" }, { "version": "217526e7ecc9f6f243e976772e81eab7ab986a4c", "lessThan": "adc34b5df5c5d87043cb500b0867fc1c4ad0117e", "status": "affected", "versionType": "git" }, { "version": "217526e7ecc9f6f243e976772e81eab7ab986a4c", "lessThan": "0763482227822f7343557f086afc382086d56c4c", "status": "affected", "versionType": "git" }, { "version": "217526e7ecc9f6f243e976772e81eab7ab986a4c", "lessThan": "83dd59ac1c3455c2c7d8ddb582d980a13199b9b3", "status": "affected", "versionType": "git" }, { "version": "217526e7ecc9f6f243e976772e81eab7ab986a4c", "lessThan": "e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1", "status": "affected", "versionType": "git" }, { "version": "217526e7ecc9f6f243e976772e81eab7ab986a4c", "lessThan": "2330b788d732f43668b965b3105b37ceb276dfea", "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": "3.17", "status": "affected" }, { "version": "0", "lessThan": "3.17", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.111", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.51", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.5", "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": "3.17", "versionEndExcluding": "6.1.191" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.17", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.17", "versionEndExcluding": "6.12.111" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.17", "versionEndExcluding": "6.18.51" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.17", "versionEndExcluding": "7.2.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.17", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/1d721729762a413015864b2a56d7fb86fb8efa9f" }, { "url": "https://git.kernel.org/stable/c/adc34b5df5c5d87043cb500b0867fc1c4ad0117e" }, { "url": "https://git.kernel.org/stable/c/0763482227822f7343557f086afc382086d56c4c" }, { "url": "https://git.kernel.org/stable/c/83dd59ac1c3455c2c7d8ddb582d980a13199b9b3" }, { "url": "https://git.kernel.org/stable/c/e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1" }, { "url": "https://git.kernel.org/stable/c/2330b788d732f43668b965b3105b37ceb276dfea" } ], "title": "NFSD: Prevent client use-after-free during close_lru reaping", "x_generator": { "engine": "bippy-1.2.0" } } } }