Prometheus Exporter Toolkit vulnerable to basic authentication bypass

Prometheus Exporter Toolkit is a utility package to build exporters. Prior to versions 0.7.2 and 0.8.2, if someone has access to a Prometheus web.yml file and users' bcrypted passwords, they can bypass security by poisoning the built-in authentication cache. Versions 0.7.2 and 0.8.2 contain a fix for the issue. There is no workaround, but attacker must have access to the hashed password to use this functionality.