libsecurity in Apple Mac OS X 10.5.8 and 10.6.4 does not properly perform comparisons to domain-name strings in X.509 certificates, which a…

libsecurity in Apple Mac OS X 10.5.8 and 10.6.4 does not properly perform comparisons to domain-name strings in X.509 certificates, which allows man-in-the-middle attackers to spoof SSL servers via a certificate associated with a similar domain name, as demonstrated by use of a www.example.con certificate to spoof www.example.com.