CVE 2008-7068
The dba_replace function in PHP 5.2.6 and 4.x allows context-dependent attackers to cause a denial of service (file truncation) via a key with the NULL byte. NOTE: this might only be a vulnerability in limited circumstances in which the attacker can modify or add database entries but does not have permissions to truncate the file.
See the 
CVE page on Mitre.org
for more details.
