{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-90038",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-09-11T19:38:34.782Z",
        "datePublished": "2026-09-16T10:33:37.366Z",
        "dateUpdated": "2026-10-19T08:56:55.673Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-10-19T08:56:55.673Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during export state revocation\n\nnfsd4_revoke_export_states() has the same use-after-free as\nnfsd4_revoke_states(): it drops nn->client_lock across\nrevoke_one_stid() and the following read of clp->cl_minorversion, but\nthe stateid reference it holds does not pin the client.  A teardown\nracing the dropped lock can free the client while revoke_one_stid()\nstill dereferences it.\n\nexportfs -u drives this path through NFSD_CMD_UNLOCK_EXPORT, so an\nadministrator removing an export can race a client expiry.\n\nSkip a client that is already expiring and otherwise pin it with\ncl_rpc_users under client_lock before dropping the lock, matching\nnfsd4_revoke_states()."
                }
            ],
            "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 UAF is in nfsd nfsd4_revoke_export_states(). A remote NFSv4 peer reaches the racing expire_client() over TCP/2049 via svc_recv to nfsd_dispatch to nfsd4_proc_compound: EXCHANGE_ID/CREATE_SESSION, SETCLIENTID_CONFIRM, or DESTROY_CLIENTID (ALLOWED_WITHOUT_FH), which free nfs4_client while the export-revoke walk still dereferences it.\nAC:L - The attacker controls the teardown side: they hold many stateids on the export so the revoke walk drops client_lock once per stid, and concurrently retry EXCHANGE_ID/CREATE_SESSION or SETCLIENTID_CONFIRM so mark_client_expired_locked() succeeds while cl_rpc_users is unpinned. The window is retryable and attacker-created.\nPR:N - EXCHANGE_ID, CREATE_SESSION, SETCLIENTID, SETCLIENTID_CONFIRM, and DESTROY_CLIENTID are ALLOWED_WITHOUT_FH with no export check. Typical AUTH_SYS/AUTH_NULL nfsd deployments do not verify RPC credentials, so any host that can reach TCP/2049 can establish state on an export and trigger expire.\nUI:N - The attacker drives the NFS compounds that create state and expire the client. Administrative exportfs -u / NFSD_CMD_UNLOCK_EXPORT is a server operational condition (unexport of the last client for a path so the filesystem can be unmounted), not a required victim user action.\nS:U - The freed object is struct nfs4_client in the NFS server kernel. Impact remains in that kernel security authority; there is no VM, IOMMU, or sandbox boundary crossing.\nC:H - revoke_one_stid() and the subsequent clp->cl_minorversion read dereference nfs4_client after free_client() kmem_cache_free's the mergeable client_slab object (KMEM_CACHE flags 0). Reclaim via EXCHANGE_ID discloses kernel memory; a UAF is C:H.\nI:H - revoke_one_stid() takes cl_lock and nfs4_put_stid() does refcount_dec_and_lock/idr_remove on the freed client's cl_lock/cl_stateids, concurrent with __destroy_client(), a slab UAF write primitive for heap corruption and control-flow hijacking.\nA:H - Use-after-free of nfs4_client in the nfsd export-revoke path oopses or panics the NFS server even without full exploitation, fully denying service of the 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": "2eac189bb059d31a29937b29ee0f477394198610",
                            "lessThan": "c05ae58fe06ce2ac34312f649e71c3596bdde358",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2eac189bb059d31a29937b29ee0f477394198610",
                            "lessThan": "2108de53568a64936a0da3e04d85c35df98d3fb6",
                            "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": "7.2",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "7.2",
                            "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": "7.2",
                                    "versionEndExcluding": "7.2.5"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "7.2",
                                    "versionEndExcluding": "7.3"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/c05ae58fe06ce2ac34312f649e71c3596bdde358"
                },
                {
                    "url": "https://git.kernel.org/stable/c/2108de53568a64936a0da3e04d85c35df98d3fb6"
                }
            ],
            "title": "NFSD: Prevent client use-after-free during export state revocation",
            "x_generator": {
                "engine": "bippy-1.2.0"
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}