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.
{ "availability": "No subscription required", "binaries": [ { "binary_version": "51.0.1+build2-0ubuntu0.14.04.1", "binary_name": "firefox" }, { "binary_version": "51.0.1+build2-0ubuntu0.14.04.1", "binary_name": "firefox-dev" }, { "binary_version": "51.0.1+build2-0ubuntu0.14.04.1", "binary_name": "firefox-globalmenu" }, { "binary_version": "51.0.1+build2-0ubuntu0.14.04.1", "binary_name": "firefox-mozsymbols" }, { "binary_version": "51.0.1+build2-0ubuntu0.14.04.1", "binary_name": "firefox-testsuite" } ] }
{ "availability": "No subscription required", "binaries": [ { "binary_version": "51.0.1+build2-0ubuntu0.16.04.1", "binary_name": "firefox" }, { "binary_version": "51.0.1+build2-0ubuntu0.16.04.1", "binary_name": "firefox-dev" }, { "binary_version": "51.0.1+build2-0ubuntu0.16.04.1", "binary_name": "firefox-globalmenu" }, { "binary_version": "51.0.1+build2-0ubuntu0.16.04.1", "binary_name": "firefox-mozsymbols" }, { "binary_version": "51.0.1+build2-0ubuntu0.16.04.1", "binary_name": "firefox-testsuite" } ] }