ext/openssl/ossl_ocsp.c in Ruby 1.8 and 1.9 does not properly check the return value from the OCSP_basic_verify function, which might allow remote attackers to successfully present an invalid X.509 certificate, possibly involving a revoked certificate.
CWE-287 - Improper Authentication
Improper (or broken) authentication attacks are widespread, and have accounted for many of the worst data breaches in recent years. Improper authentication attacks are a class of vulnerabilities where an attacker impersonates a legitimate user by exploiting weaknesses in either session management or credential management to gain access to the user’s account. This can result in disclosure of sensitive information, and can lead to system compromise, theft, identity theft, and fraud.