general/login.php in phpCollab 2.5 rc3 and earlier allows remote attackers to execute arbitrary commands via shell metacharacters in unspecified input related to the SSL_CLIENT_CERT environment variable. NOTE: in some environments, SSL_CLIENT_CERT always has a base64-encoded string value, which may impose constraints on injection for typical shells.
Improper Neutralization of Special Elements used in an OS Command The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command before it is sent to a downstream component.