WebExtensions could use the "mozAddonManager" API by modifying the CSP headers on sites with the appropriate permissions and then using host requests to…

WebExtensions could use the "mozAddonManager" API by modifying the CSP headers on sites with the appropriate permissions and then using host requests to redirect script loads to a malicious site. This allows a malicious extension to then install additional extensions without explicit user permission. This vulnerability affects Firefox < 51.