OpenSSL is a toolkit that implements Secure Sockets Layer and Transport Layer Security protocols as well as a full-strength, general purpose, cryptography library. The Google security team discovered a flaw in the way OpenSSL checked the verification of certificates. An attacker in control of a malicious server, or able to effect a "man in the middle" attack, could present a malformed SSL/TLS signature from a certificate chain to a vulnerable client and bypass validation. All OpenSSL users should upgrade to these updated packages, which contain backported patches to resolve these issues. For the update to take effect, all running OpenSSL client applications must be restarted, or the system rebooted.