OpenAM before 16.1.4 contains a server-side request forgery vulnerability in certificate CRL checking that fetches CRLs from the distribution point named in a presented certificate without restricting the destination or verifying the downloaded CRL's signature. Attackers holding a trusted-CA-chained certificate can make OpenAM request internal hosts, capture configured CRL update credentials, overwrite stored revocation data to block certificate authentication for that CA, and tie up authentication threads.