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vuln-cve/data/2026/89xxx/CVE-2026-89671.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-89671",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2026-09-11T19:38:34.746Z",
"datePublished": "2026-09-11T19:45:56.604Z",
"dateUpdated": "2026-10-30T12:32:36.627Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-10-30T12:32:36.627Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: gate nfs3 setacl by argp->mask\n\nnfsd3_proc_setacl() calls set_posix_acl() unconditionally for both\nACL_TYPE_ACCESS and ACL_TYPE_DEFAULT, passing argp->acl_access and\nargp->acl_default verbatim. The NFSv3 ACL decoder only populates\nthose pointers when the corresponding mask bit is set:\n\n nfs3svc_decode_setaclargs()\n if (args->mask & NFS_ACL) decode into acl_access\n if (args->mask & NFS_DFACL) decode into acl_default\n /* otherwise the pointer stays NULL (pc_argzero) */\n\n nfsd3_proc_setacl()\n set_posix_acl(.., ACL_TYPE_ACCESS, argp->acl_access)\n set_posix_acl(.., ACL_TYPE_DEFAULT, argp->acl_default)\n\nset_posix_acl(idmap, dentry, type, NULL) is the VFS \"remove this\nACL type\" operation. A NULL pointer that means \"the client did not\nsend this arm\" is therefore indistinguishable from \"the client\nasked to remove this ACL\". A SETACL with mask=NFS_ACL silently\ndrops the directory's default ACL; mask=0 drops both.\n\nThe sibling nfsd3_proc_getacl() already consults argp->mask before\ntouching each arm; mirror that in setacl.\n\nFix by wrapping each set_posix_acl() call in the matching mask bit\ncheck and initializing error to 0 before inode_lock so that a\nrequest with neither bit set leaves the on-disk ACLs untouched and\nreturns nfs_ok. The out_drop_lock path and the unconditional\nposix_acl_release() at out: are preserved; both NULL-tolerate the\nskipped arms."
}
],
"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:N",
"baseScore": 9.1,
"baseSeverity": "CRITICAL"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - nfsd3_proc_setacl() is NFSACL v3 SETACL (RPC program 100227) on the in-kernel NFS server, reached over TCP/UDP (typically port 2049) from a remote peer; no local syscall or physical access is required.\nAC:L - A single SETACL with mask omitting NFS_ACL and/or NFS_DFACL reliably deletes the corresponding POSIX ACL; there is no race or attacker-uncontrollable layout, and CONFIG_NFSD_V3_ACL is enabled on common distro NFS server kernels.\nPR:N - Default nfsd exports accept AUTH_UNIX and AUTH_NULL with no shared secret; AUTH_UNIX UIDs are attacker-chosen, so the caller spoofs the inode owner to pass inode_owner_or_capable() without any account on the server.\nUI:N - The attacker triggers the flaw by sending crafted NFSACL SETACL RPCs; no victim must mount a filesystem, open a file, or otherwise interact.\nS:U - Impact stays on POSIX ACL metadata of the exported filesystem in the same kernel/host security authority; this is not a VM escape, IOMMU bypass, or sandbox breakout.\nC:H - Removing an access ACL drops named-user/group entries that may be the only restriction beyond mode bits, and removing a directory default ACL stops inheritance of restrictive policy, so ACL-protected file contents can become readable.\nI:H - set_posix_acl(..., NULL) is the VFS remove-ACL operation, so an omitted mask bit silently deletes that ACL type on disk; mask=NFS_ACL strips the default ACL and mask=0 strips both, destroying access-control metadata.\nA:N - The path performs a defined VFS ACL-remove and does not oops, panic, hang, deadlock, or leak kernel memory, so nfsd and the host remain available."
}
]
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"fs/nfsd/nfs3acl.c"
],
"versions": [
{
"version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055",
"lessThan": "beeb33152873ad40692bd255b562966f8ba43dbd",
"status": "affected",
"versionType": "git"
},
{
"version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055",
"lessThan": "3be1d8611dae4829e4608007db29f4a8748c37b2",
"status": "affected",
"versionType": "git"
},
{
"version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055",
"lessThan": "68a80b26efdff1d09f8ae1773c6a915abb9e191d",
"status": "affected",
"versionType": "git"
},
{
"version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055",
"lessThan": "b3bff820d068ea59767d4e91a3258231a879da5f",
"status": "affected",
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},
{
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"status": "affected",
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"lessThan": "453d7198a0ab07a12d46e0575861ac7b932da17e",
"status": "affected",
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}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"fs/nfsd/nfs3acl.c"
],
"versions": [
{
"version": "2.6.13",
"status": "affected"
},
{
"version": "0",
"lessThan": "2.6.13",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.1.191",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.6.157",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.12.109",
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.18.50",
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.2.4",
"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": "2.6.13",
"versionEndExcluding": "6.1.191"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "2.6.13",
"versionEndExcluding": "6.6.157"
},
{
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionEndExcluding": "6.12.109"
},
{
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "2.6.13",
"versionEndExcluding": "6.18.50"
},
{
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionEndExcluding": "7.2.4"
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{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionEndExcluding": "7.3"
}
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],
"references": [
{
"url": "https://git.kernel.org/stable/c/beeb33152873ad40692bd255b562966f8ba43dbd"
},
{
"url": "https://git.kernel.org/stable/c/3be1d8611dae4829e4608007db29f4a8748c37b2"
},
{
"url": "https://git.kernel.org/stable/c/68a80b26efdff1d09f8ae1773c6a915abb9e191d"
},
{
"url": "https://git.kernel.org/stable/c/b3bff820d068ea59767d4e91a3258231a879da5f"
},
{
"url": "https://git.kernel.org/stable/c/ff99ed007f065198fd723152405c22aa558f700b"
},
{
"url": "https://git.kernel.org/stable/c/453d7198a0ab07a12d46e0575861ac7b932da17e"
}
],
"title": "nfsd: gate nfs3 setacl by argp->mask",
"x_generator": {
"engine": "bippy-1.2.0"
}
},
"adp": [
{
"metrics": [
{
"other": {
"type": "ssvc",
"content": {
"id": "CVE-2026-89671",
"role": "CISA Coordinator",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "total"
}
],
"version": "2.0.3",
"timestamp": "2026-10-16T19:25:43.543380Z"
}
}
}
],
"title": "CISA ADP Vulnrichment",
"providerMetadata": {
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP",
"dateUpdated": "2026-10-16T19:26:48.048Z"
}
}
]
}
}