The TLS implementation in Opera before 12.13 does not properly consider timing side-channel attacks on a MAC check operation during the processing of malformed CBC padding, which allows remote attackers to conduct distinguishing attacks and plaintext-recovery attacks via statistical analysis of timing data for crafted packets, a related issue to CVE-2013-0169.
http://www.opera.com/support/kb/view/1044/
http://www.opera.com/docs/changelogs/unified/1213/
http://www.isg.rhul.ac.uk/tls/TLStiming.pdf
http://openwall.com/lists/oss-security/2013/02/05/24
http://lists.opensuse.org/opensuse-updates/2013-02/msg00038.html