Debian Linux Security Advisory 3436-1 – Karthikeyan Bhargavan and Gaetan Leurent at INRIA discovered a flaw in the TLS 1.2 protocol which could allow the MD5 hash function to be used for signing ServerKeyExchange and Client Authentication packets during a TLS handshake. A man-in-the-middle attacker could exploit this flaw to conduct collision attacks to impersonate a TLS server or an authenticated TLS client.