The ExpandCert function in Apache-SSL before apache_1.3.41+ssl_1.59 does not properly handle (1) '/' and (2) '=' characters in a Distinguished Name (DN) in a client certificate, which might allow remote attackers to bypass authentication via a crafted DN that triggers overwriting of environment variables.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.