A flaw was found in the way TLS 1.2 could use the MD5 hash function for signing ServerKeyExchange and Client Authentication packets during a TLS handshake. A man-in-the-middle attacker able to force a TLS connection to use the MD5 hash function could use this flaw to conduct collision attacks to impersonate a TLS server or an authenticated TLS client.

Mozilla Firefox could provide weaker than expected security, caused by the creation of incorrect calculations in certain cases by the Network Security Services (NSS) mpdiv() and mpexptmod() functions. An attacker could exploit this vulnerability to create cryptographic weaknesses.