{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-53394", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-06-09T07:44:35.402Z", "datePublished": "2026-07-19T12:01:57.261Z", "dateUpdated": "2026-08-17T04:50:45.946Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:50:45.946Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: avoid leaking pre-allocated openowner on unconfirmed retry race\n\nWhen find_or_alloc_open_stateowner() encounters an unconfirmed owner, it\ncalls release_openowner() and sets oo = NULL. Control then falls through\npast the `if (oo)` guard -- which would have freed any pre-allocated\n`new` -- and unconditionally executes `new = alloc_stateowner(...)`. If\n`new` was already allocated on a prior iteration, the pointer is\nsilently overwritten and the previous allocation (slab object + owner\nname buffer) is leaked.\n\nThis requires a race: two NFSv4.0 OPEN threads with the same owner\nstring, where a concurrent thread inserts a new unconfirmed owner into\nthe hash between retry iterations. The window is narrow but repeatable\nunder adversarial conditions.\n\nFix by adding `goto retry` after `oo = NULL` so the already-allocated\n`new` is reused on the next iteration rather than overwritten." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The flaw is in nfsd's NFSv4 OPEN handling, reachable remotely via NFS RPC on TCP/UDP port 2049 through svc_recv → NFSPROC4_COMPOUND → nfsd4_open → nfsd4_process_open1 → find_or_alloc_open_stateowner().\nAC:L - Exploitation requires a race between two NFSv4.0 OPEN requests with the same owner string, but the attacker controls both sides by issuing concurrent compounds from multiple connections; the fix commit itself states this is repeatable under adversarial conditions.\nPR:N - No local privileges on the server are required—only remote NFSv4 client access to establish a clientid (SETCLIENTID/CONFIRM) and send concurrent OPEN operations; the leak occurs in nfsd4_process_open1 before export/file permission checks complete.\nUI:N - Exploitation is fully automated via concurrent NFS protocol requests and requires no action from any victim user on the server or client side.\nS:U - Impact is confined to kernel memory consumption within nfsd's security authority; there is no cross-boundary escape to other components or privilege domains.\nC:N - This is a pure memory leak where orphaned slab objects lose all kernel references; no out-of-bounds read, use-after-free, or other mechanism exposes kernel data to the attacker.\nI:N - The bug silently drops a pointer to an allocated object without corrupting adjacent memory or providing any write or control-flow primitive—only heap memory is lost.\nA:H - Each successful race leaks a slab object plus an attacker-controlled owner-name buffer (up to NFS4_OPAQUE_LIMIT bytes), and the attack can be repeated indefinitely to cause unbounded kernel memory exhaustion, denying NFS service and potentially triggering system-wide OOM conditions." } ] } ], "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": "23df17788c6212809848f836b10c4f85b16843a5", "lessThan": "c9aefb2b5f11337c9202c5bd0c45d71198449718", "status": "affected", "versionType": "git" }, { "version": "23df17788c6212809848f836b10c4f85b16843a5", "lessThan": "017a6150106b054cc84d1b0582d97bd3a74d4281", "status": "affected", "versionType": "git" }, { "version": "23df17788c6212809848f836b10c4f85b16843a5", "lessThan": "a10bf67fe06469a71a401f72f328237345d553c0", "status": "affected", "versionType": "git" }, { "version": "23df17788c6212809848f836b10c4f85b16843a5", "lessThan": "57aee7a35bb12753057c5b65d72d1f46c0e95b07", "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": "6.10", "status": "affected" }, { "version": "0", "lessThan": "6.10", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.95", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.38", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.3", "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": "6.10", "versionEndExcluding": "6.12.95" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.18.38" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "7.1.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/c9aefb2b5f11337c9202c5bd0c45d71198449718" }, { "url": "https://git.kernel.org/stable/c/017a6150106b054cc84d1b0582d97bd3a74d4281" }, { "url": "https://git.kernel.org/stable/c/a10bf67fe06469a71a401f72f328237345d553c0" }, { "url": "https://git.kernel.org/stable/c/57aee7a35bb12753057c5b65d72d1f46c0e95b07" } ], "title": "nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race", "x_generator": { "engine": "bippy-1.2.0" } } } }