The (1) serf_ssl_cert_issuer, (2) serf_ssl_cert_subject, and (3) serf_-
ssl_cert_certificate functions in Serf 0.2.0 through 1.3.x before 1.3.7
does not properly handle a NUL byte in a domain name in the subject's
Common Name (CN) field of an X.509 certificate, which allows man-in-
the-middle attackers to spoof arbitrary SSL servers via a crafted
certificate issued by a legitimate Certification Authority.