Using iterative requests an attacker was able to learn the size of an opaque response, as well as the contents of a server-supplied Vary header. This vulnerability affects Firefox < 119.
{ "binaries": [ { "binary_name": "firefox", "binary_version": "119.0+build2-0ubuntu0.20.04.1" }, { "binary_name": "firefox-dev", "binary_version": "119.0+build2-0ubuntu0.20.04.1" }, { "binary_name": "firefox-geckodriver", "binary_version": "119.0+build2-0ubuntu0.20.04.1" }, { "binary_name": "firefox-mozsymbols", "binary_version": "119.0+build2-0ubuntu0.20.04.1" } ], "availability": "No subscription required" }