php-mbstring -- php mbstring buffer overflow vulnerability

SecurityFocus reports:

PHP is prone to a buffer-overflow vulnerability because it fails to perform boundary checks before copying user-supplied data to insufficiently sized memory buffers. The issue affects the 'mbstring' extension included in the standard distribution.

An attacker can exploit this issue to execute arbitrary machine code in the context of the affected webserver. Failed exploit attempts will likely crash the webserver, denying service to legitimate users.

[source]