{"id":"CVE-2026-89671","summary":"nfsd: gate nfs3 setacl by argp-\u003emask","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 & NFS_ACL)    decode into acl_access\n      if (args-\u003emask & 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.","modified":"2026-09-13T03:47:20.144270474Z","published":"2026-09-11T19:45:56.604Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89671.json"},"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055"},{"fixed":"68a80b26efdff1d09f8ae1773c6a915abb9e191d"},{"fixed":"b3bff820d068ea59767d4e91a3258231a879da5f"},{"fixed":"ff99ed007f065198fd723152405c22aa558f700b"},{"fixed":"453d7198a0ab07a12d46e0575861ac7b932da17e"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89671.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","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"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89671.json"}}],"schema_version":"1.9.0"}