Mozilla Firefox versions before 3.0.13 and 3.5.0 are affected by multiple vulnerabilities:
Compromise of SSL-protected communication (MFSA 2009-42).
A mismatch has been reported in the treatment of domain names in SSL certificates between
SSL clients and the Certificate Authorities (CA) which issue server certificates. In
particular, if a malicious person requested a certificate for a host name with an invalid
null character in it most CAs would issue the certificate if the requester owned the domain
specified after the null, while most SSL clients (browsers) ignored that part of the name
and used the unvalidated part in front of the null. This made it possible for attackers to
obtain certificates that would function for any site they wished to target. These
certificates could be used to intercept and potentially alter encrypted communication
between the client and a server such as sensitive bank account transactions.
Heap overflow in certificate regexp parsing (MFSA 2009-43).
A heap overflow vulnerability has been reported in the code that handles regular
expressions in certificate names. This vulnerability could be used to compromise the
browser and run arbitrary code by presenting a specially crafted certificate to the
client. This code provided compatibility with the non-standard regular expression
syntax historically supported by Netscape clients and servers. With version 3.5
Firefox switched to the more limited industry-standard wildcard syntax instead and
is not vulnerable to this flaw.