If a valid external protocol handler was referenced in an image tag, the resulting broken image size could be distinguished from a broken image size of a non-existent protocol handler. This allowed an attacker to successfully probe whether an external protocol handler was registered. This vulnerability affects Firefox < 82. Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15680 Reference (s):
- https://bugzilla.mozilla.org/show_bug.cgi?id=1658881
- URL: https://bugzilla.mozilla.org/show_bug.cgi?id=1658881
- https://www.mozilla.org/security/advisories/mfsa2020-45/
- URL: https://www.mozilla.org/security/advisories/mfsa2020-45/