Debian Security Advisory 1719-1 – Martin von Gagern discovered that GNUTLS, an implementation of the TLS/SSL protocol, handles verification of X.509 certificate chains incorrectly if a self-signed certificate is configured as a trusted certificate. This could cause clients to accept forged server certificates as genuine.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/74815/dsa-1719-1.txt
Source: https://packetstormsecurity.com/files/74815/Debian-Linux-Security-Advisory-1719-1.html