This indicates an attack attempt against a Cryptographic vulnerability in Mozilla Network Security Services.
The vulnerability is due to improper verification of cryptographic signatures in the affected library. A remote attacker may exploit this to access sensitive information via a forged certificate.
Mozilla Foundation Network Security Services prior to 184.108.40.206
Mozilla Foundation Network Security Services prior to 3.16.5
Mozilla Foundation Network Security Services prior to 3.17.1
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems.
Apply the latest update from the vendor.