CVE 2011-0421

The _zip_name_locate function in zip_name_locate.c in the Zip extension in PHP before 5.3.6 does not properly handle a ZIPARCHIVE::FL_UNCHANGED argument, which might allow context-dependent attackers to cause a denial of service (NULL pointer dereference) via an empty ZIP archive that is processed with a (1) locateName or (2) statName operation.

See the CVE page on Mitre.org for more details.