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FKIE_CVE-2026-89671

Vulnerability from fkie_nvd - Published: 2026-09-11 20:19 - Updated: 2026-09-14 13:19
Severity
9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: gate nfs3 setacl by argp->mask nfsd3_proc_setacl() calls set_posix_acl() unconditionally for both ACL_TYPE_ACCESS and ACL_TYPE_DEFAULT, passing argp->acl_access and argp->acl_default verbatim. The NFSv3 ACL decoder only populates those pointers when the corresponding mask bit is set: nfs3svc_decode_setaclargs() if (args->mask & NFS_ACL) decode into acl_access if (args->mask & NFS_DFACL) decode into acl_default /* otherwise the pointer stays NULL (pc_argzero) */ nfsd3_proc_setacl() set_posix_acl(.., ACL_TYPE_ACCESS, argp->acl_access) set_posix_acl(.., ACL_TYPE_DEFAULT, argp->acl_default) set_posix_acl(idmap, dentry, type, NULL) is the VFS "remove this ACL type" operation. A NULL pointer that means "the client did not send this arm" is therefore indistinguishable from "the client asked to remove this ACL". A SETACL with mask=NFS_ACL silently drops the directory's default ACL; mask=0 drops both. The sibling nfsd3_proc_getacl() already consults argp->mask before touching each arm; mirror that in setacl. Fix by wrapping each set_posix_acl() call in the matching mask bit check and initializing error to 0 before inode_lock so that a request with neither bit set leaves the on-disk ACLs untouched and returns nfs_ok. The out_drop_lock path and the unconditional posix_acl_release() at out: are preserved; both NULL-tolerate the skipped arms.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3be1d8611dae4829e4608007db29f4a8748c37b2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/453d7198a0ab07a12d46e0575861ac7b932da17e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/68a80b26efdff1d09f8ae1773c6a915abb9e191d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b3bff820d068ea59767d4e91a3258231a879da5f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ff99ed007f065198fd723152405c22aa558f700b
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs3acl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3be1d8611dae4829e4608007db29f4a8748c37b2",
              "status": "affected",
              "version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055",
              "versionType": "git"
            },
            {
              "lessThan": "68a80b26efdff1d09f8ae1773c6a915abb9e191d",
              "status": "affected",
              "version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055",
              "versionType": "git"
            },
            {
              "lessThan": "b3bff820d068ea59767d4e91a3258231a879da5f",
              "status": "affected",
              "version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055",
              "versionType": "git"
            },
            {
              "lessThan": "ff99ed007f065198fd723152405c22aa558f700b",
              "status": "affected",
              "version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055",
              "versionType": "git"
            },
            {
              "lessThan": "453d7198a0ab07a12d46e0575861ac7b932da17e",
              "status": "affected",
              "version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs3acl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.13"
            },
            {
              "lessThan": "2.6.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: gate nfs3 setacl by argp-\u003emask\n\nnfsd3_proc_setacl() calls set_posix_acl() unconditionally for both\nACL_TYPE_ACCESS and ACL_TYPE_DEFAULT, passing argp-\u003eacl_access and\nargp-\u003eacl_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-\u003emask \u0026 NFS_ACL)    decode into acl_access\n      if (args-\u003emask \u0026 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-\u003eacl_access)\n      set_posix_acl(.., ACL_TYPE_DEFAULT, argp-\u003eacl_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\u0027s default ACL; mask=0 drops both.\n\nThe sibling nfsd3_proc_getacl() already consults argp-\u003emask 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."
    }
  ],
  "id": "CVE-2026-89671",
  "lastModified": "2026-09-14T13:19:19.040",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-11T20:19:53.647",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3be1d8611dae4829e4608007db29f4a8748c37b2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/453d7198a0ab07a12d46e0575861ac7b932da17e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/68a80b26efdff1d09f8ae1773c6a915abb9e191d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b3bff820d068ea59767d4e91a3258231a879da5f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ff99ed007f065198fd723152405c22aa558f700b"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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