source: https://www.securityfocus.com/bid/30488/info Apple Mac OS X is prone to multiple memory-corruption vulnerabilities that affect the CoreGraphics component. Attackers can exploit these issues to execute arbitrary code in the context of the affected application or cause denial-of-service conditions. The following versions are affected: Mac OS X v10.4.11 and prior Mac OS X Server v10.4.11 and prior Mac OS X v10.5.4 and prior Mac OS X Server v10.5.4 and prior NOTE: These issues were previously covered in BID 30483 (Apple Mac OS X 2008-005 Multiple Security Vulnerabilities), but have been given their own record to better document them. fuzzer by lcamtuf@coredump.cx

Deallocate canvas after every cycle (NULL ptr in Safari, likely exploitable in Opera)
Keep context (if combined with above, NULL ptr Firefox, likely exploitable in Opera)
Use large canvas scaling (likely exploitable in Opera, bogs down Firefox)
Return undefined values (NULL ptr Safari, may hang Opera)
Return large integers (exploitable crash in Safari, OOM/DoS elsewhere)
Skip time-consuming operations (quicker, but may miss issues)