{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055"
            },
            {
              "fixed": "68a80b26efdff1d09f8ae1773c6a915abb9e191d"
            },
            {
              "fixed": "b3bff820d068ea59767d4e91a3258231a879da5f"
            },
            {
              "fixed": "ff99ed007f065198fd723152405c22aa558f700b"
            },
            {
              "fixed": "453d7198a0ab07a12d46e0575861ac7b932da17e"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.13"
            },
            {
              "fixed": "6.12.109"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.50"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89671.json"
  },
  "details": "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's 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",
  "modified": "2026-09-13T03:30:35.880899799Z",
  "published": "2026-09-11T19:45:56.604Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/453d7198a0ab07a12d46e0575861ac7b932da17e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/68a80b26efdff1d09f8ae1773c6a915abb9e191d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b3bff820d068ea59767d4e91a3258231a879da5f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ff99ed007f065198fd723152405c22aa558f700b"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89671.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89671"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "nfsd: gate nfs3 setacl by argp-\u003emask"
}