The remote Debian host is missing a security-related update.
Lalith Rallabhandi discovered that OmniAuth, a Ruby library for implementing multi-provider authentication in web applications, mishandled and leaked sensitive information. An attacker with access to the callback environment, such as in the case of a crafted web application, can request authentication services from this module and access to the CSRF token.
Upgrade the ruby-omniauth packages. For the oldstable distribution (jessie), this problem has been fixed in version 1.2.1-1+deb8u1. For the stable distribution (stretch), this problem has been fixed in version 1.3.1-1+deb9u1.