The SSL 3 HMAC functionality in wolfSSL CyaSSL 2.5.0 before 2.9.4 does not check the padding length when verification fails, which allows remote attackers to have unspecified impact via a crafted HMAC, which triggers an out-of-bounds read.
http://www.wolfssl.com/yaSSL/Docs-cyassl-changelog.html
http://www.wolfssl.com/yaSSL/Blog/Entries/2014/4/11_wolfSSL_Security_Advisory__April_9%2C_2014.html