{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-74315",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-08-15T05:44:03.883Z",
        "datePublished": "2026-08-15T05:58:13.504Z",
        "dateUpdated": "2026-08-17T05:45:48.282Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-17T05:45:48.282Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlockd: Avoid hashing uninitialized bytes in nlm4svc_lookup_file()\n\nfile_hash() digests the first LOCKD_FH_HASH_SIZE bytes of\nnfs_fh.data when bucketing nlm_files[], independent of fh.size.\nCommit 3de744ee4e45 (\"lockd: Use xdrgen XDR functions for the\nNLMv4 TEST procedure\") set .pc_argzero to zero for the converted\nprocedures and moved file-handle population into\nnlm4svc_lookup_file(), which copies only xdr_lock->fh.len bytes\ninto lock->fh.data.\n\nWhen an NLMv4 client presents a file handle shorter than\nLOCKD_FH_HASH_SIZE, bytes fh.len..31 retain whatever the argument\nbuffer held from an earlier request.  The same wire handle then\nhashes to different buckets across calls; nlm_lookup_file() misses\nthe existing nlm_file entry, and lock-state lookups fail.\n\nZero only the tail bytes that file_hash() would otherwise consume.\nHandles of LOCKD_FH_HASH_SIZE or larger already populate every byte\nthat file_hash() reads."
                }
            ],
            "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 bug is reached via remote NLMv4 RPC to in-kernel lockd (TCP/UDP SunRPC, typically alongside nfsd), from svc_process() through nlm4svc_proc_* handlers into nlm4svc_lookup_file() and nlm_lookup_file().\nAC:L - An NFS client can reliably trigger this by sending NLMv4 LOCK/TEST/SHARE/etc. with a file handle shorter than 32 bytes; stale tail bytes come from the same worker's prior RPC argument buffer, which the attacker can influence with earlier requests.\nPR:N - lockd_authenticate() accepts RPC_AUTH_NULL/RPC_AUTH_UNIX and, for normal procedures, svc_set_client(); no local UID, capabilities, or root in the host namespace is required—only network reachability as an NFS export client (AUTH_NULL is explicitly supported for NLM).\nUI:N - Exploitation requires only crafted NLMv4 RPC traffic to a running lockd/nfsd instance; no victim mount, file open, or other interactive action beyond normal NFS client participation.\nS:U - Impact is confined to the NFS server's kernel lockd/nfsd authority (file-lock and DOS-share state on exported files); it does not cross VM, container, or IOMMU security boundaries.\nC:H - file_hash() sums the first 32 bytes of nfs_fh.data regardless of fh.size; when fh.len<32, bytes fh.len..31 are stale prior-request buffer contents, so each lookup performs an out-of-bounds read of up to 31 bytes used in security-relevant file-table indexing.\nI:H - Inconsistent hashing creates duplicate nlm_file entries for the same wire handle; per-entry f_shares and nlm_block state diverge while both open the same inode, enabling DOS share-mode bypass and incorrect lock/block bookkeeping despite VFS-level enforcement.\nA:H - Missed nlm_file lookups cause lock-state lookup failures, incorrect NLM responses, hung or failing NFS lock clients, and unbounded duplicate nlm_file/VFS opens that can exhaust server lock-manager resources on production NFS file servers."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/lockd/lockd.h",
                        "fs/lockd/svc4proc.c",
                        "fs/lockd/svcsubs.c"
                    ],
                    "versions": [
                        {
                            "version": "3de744ee4e4557da0d63be8a97ad44b4dad58912",
                            "lessThan": "686c2434f9f16b87aeed18d76cc562df9f2695ab",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "3de744ee4e4557da0d63be8a97ad44b4dad58912",
                            "lessThan": "6e4c62caecf792e8a15ad9bc7f371e57c17e3302",
                            "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/lockd.h",
                        "fs/lockd/svc4proc.c",
                        "fs/lockd/svcsubs.c"
                    ],
                    "versions": [
                        {
                            "version": "7.1",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "7.1",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.1.5",
                            "lessThanOrEqual": "7.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2",
                            "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": "7.1",
                                    "versionEndExcluding": "7.1.5"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "7.1",
                                    "versionEndExcluding": "7.2"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/686c2434f9f16b87aeed18d76cc562df9f2695ab"
                },
                {
                    "url": "https://git.kernel.org/stable/c/6e4c62caecf792e8a15ad9bc7f371e57c17e3302"
                }
            ],
            "title": "lockd: Avoid hashing uninitialized bytes in nlm4svc_lookup_file()",
            "x_generator": {
                "engine": "bippy-1.2.0"
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        }
    }
}