Multiple use-after-free vulnerabilities in libxml2 2.5.10, 2.6.16, 2.6.26, 2.6.27, and 2.6.32, and libxml 1.8.17, allow context-dependent attackers to cause a denial of service (application crash) via crafted (1) Notation or (2) Enumeration attribute types in an XML file, as demonstrated by the Codenomicon XML fuzzing framework.

The gnutlsx509verifycertificate function in lib/x509/verify.c in libgnutls in GnuTLS before 2.6.1 trusts certificate chains in which the last certificate is an arbitrary trusted, self-signed certificate, which allows man-in-the-middle attackers to insert a spoofed certificate for any Distinguished Name (DN).

In his upcoming Blackhat paper and presentation Dan Kaminsky highlights some more issues he has found relating to SSL hash collisions and related vulnerabilities.

His second issue is all about inconsistencies in the interpretation of subject x509 names in certificates. Specifically "issue 2, attack 2c" regarding NULL terminators in a Common Name field. An attacker could create a malicious certificate containing a NULL, which, if they were able to get it signed, could confuse a client into accepting it by mistake.

According to the paper this is said to affect Firefox.