CRLF injection vulnerability in PHP 4.2.1 through 4.2.3, when allow_url_fopen is enabled, allows remote attackers to modify HTTP headers for outgoing requests by causing CRLF sequences to be injected into arguments that are passed to the (1) fopen or (2) file functions.

The imap_header function in the IMAP functionality for PHP before 4.3.0 allows remote attackers to cause a denial of service via an e-mail message with a large number of "To" addresses, which triggers an error in the rfc822_write_address function.

php.exe in PHP 3.0 through 4.2.2, when running on Apache, does not terminate properly, which allows remote attackers to cause a denial of service via a direct request without arguments.

Argument injection vulnerability in the mail function for PHP 4.x to 4.2.2 may allow attackers to bypass safe mode restrictions and modify command line arguments to the MTA (e.g. sendmail) in the 5th argument to mail(), altering MTA behavior and possibly executing commands.

The mail function in PHP 4.x to 4.2.2 does not filter ASCII control characters from its arguments, which could allow remote attackers to modify mail message content, including mail headers, and possibly use PHP as a "spam proxy."