Dancer::Plugin::Auth::Google versions before 0.08 for Perl have TLS verification disabled.
The default user agent is initialised with SSLverifymode explicitly disabled.
An attacker with network man-in-the-middle (MITM) capability between the Dancer application and googleapis.com can intercept the OAuth2 token exchange and userinfo fetch, return a forged accesstoken and user profile, and be logged in to the Dancer application as any Google user.