The ANI parser in Microsoft Windows before 7 on the x86 platform, as used in Internet Explorer and other applications, allows remote attackers to cause a denial of service (memory and CPU consumption) via a crafted biClrUsed value in the BITMAPINFO header of a .ANI file.
https://exchange.xforce.ibmcloud.com/vulnerabilities/56756
http://skypher.com/index.php/2010/03/08/ani-file-bitmapinfoheader-biclrused-bounds-check-missing/