User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the code responsible for parsing Director's RIFF-based file format. While parsing the tSAC chunk, the DIRAPI module does not properly verify the signedness of a count value within an undocumented structure. By providing a large enough negative value a pointer can be miscalculated leading to memory corruption. This can be exploited by a remote attacker to execute arbitrary code under the context of the user running the web browser.