A Null pointer dereference vulnerability exists in Mozilla Network Security Services due to a missing NULL check in PK11_SignWithSymKey / ssl3_ComputeRecordMACConstantTime, which could let a remote malicious user cause a Denial of Service.

The Network Security Services (NSS) library before 3.12.3, as used in Firefox; GnuTLS before 2.6.4 and 2.7.4; OpenSSL 0.9.8 through 0.9.8k; and other products support MD2 with X.509 certificates, which might allow remote attackers to spoof certificates by using MD2 design flaws to generate a hash collision in less than brute-force time. NOTE: the scope of this issue is currently limited because the amount of computation required is still large.