Multiple buffer overflows in a certain ActiveX control in CryptoX.dll 2.0 and earlier in the Ultra Crypto Component allow remote attackers to execute arbitrary code via (1) a long string in the first argument to the AcquireContext method or (2) an unspecified vector to the DeleteContext method.
https://www.exploit-db.com/exploits/4389
https://exchange.xforce.ibmcloud.com/vulnerabilities/36524