PHP before 5.4.40, 5.5.x before 5.5.24, and 5.6.x before 5.6.8 does not ensure that pathnames lack %00 sequences, which might allow remote attackers to read or write to arbitrary files via crafted input to an application that calls (1) a DOMDocument load method, (2) the xmlwriter_open_uri function, (3) the finfo_file function, or (4) the hash_hmac_file function, as demonstrated by a filename\0.xml attack that bypasses an intended configuration in which client users may read only .xml files.