Request for help PHP v3.0.12

Can anyone help me with a possible security problem with PHP v 3.0.12? I am led to believe that if a hacker manages to deliberately overflow the system buffer, then a piece of executable code can be placed in the buffer which can then execute to thereby breach the security of the server. Is anyone aware of this problem? thanks Ian ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. **********************************************************************