A potential buffer overflow was found in the code used to handle RealMedia RTSP streams. When checking for matching asm rules, the code stores the results in a fixed-size array, but no boundary checks are performed. This may lead to a buffer overflow if the user is tricked into connecting to a malicious server. Since the attacker cannot write arbitrary data into the buffer, creating an exploit is very hard; but a DoS attack is easily made. A fix for this problem was committed to SVN on Sun Dec 31 13:27:53 2006 UTC as r21799. The fix involves three files: stream/realrtsp/asmrp.c, stream/realrtsp/asmrp.h and stream/realrtsp/real.c.