Buffer overflow in the imap_fetch_overview function in the IMAP functionality (php_imap.c) in PHP before 4.3.3 allows remote attackers to cause a denial of service (segmentation fault) and possibly execute arbitrary code via a long e-mail address in a (1) To or (2) From header.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10346