Joonas Kuorilehto discovered that GNU TLS performed insufficient
validation of session IDs during TLS/SSL handshakes. A malicious server
could use this to execute arbitrary code or perform denial of service.
For the stable distribution (wheezy), this problem has been fixed in
version 2.12.20-8+deb7u2.
For the unstable distribution (sid), this problem has been fixed in
version 2.12.23-16.
We recommend that you upgrade your gnutls26 packages.