nCipher Security Advisory No. 13 – Application programmers using the nCore API to calculate and verify CBC MACs may have accidentally implemented a MAC protocol which fails to detect certain modifications to messages it is supposed to protect.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/44526/nCipher13.txt
Source: https://packetstormsecurity.com/files/44526/nCipher13.txt.html