Firefox normally asks for confirmation before asking the operating system to find an application to handle a scheme that the browser does not support. It did not ask before doing so for the Usenet-related schemes news: and snews:. Since most operating systems don't have a trusted newsreader installed by default, an unscrupulous program that the user downloaded could register itself as a handler. The website that served the application download could then launch that application at will. This vulnerability affects Firefox < 130, Firefox ESR < 128.2, and Firefox ESR < 115.15.
{ "binaries": [ { "binary_version": "130.0+build2-0ubuntu0.20.04.1", "binary_name": "firefox" }, { "binary_version": "130.0+build2-0ubuntu0.20.04.1", "binary_name": "firefox-dev" }, { "binary_version": "130.0+build2-0ubuntu0.20.04.1", "binary_name": "firefox-geckodriver" }, { "binary_version": "130.0+build2-0ubuntu0.20.04.1", "binary_name": "firefox-mozsymbols" } ], "availability": "No subscription required" }