Barracuda Web Filter before 8.1.0.005, when SSL Inspection is enabled, does not verify X.509 certificates from upstream SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.
https://www.barracuda.com/support/techalerts
https://techlib.barracuda.com/BWF/UpdateSSLCerts
https://blog.barracuda.com/2015/04/28/barracuda-delivers-updated-ssl-inspection-feature/