CVE-2025-6425 The WebCompat WebExtension shipped with Firefox exposed a persistent UUID

An attacker who enumerated resources from the WebCompat extension could have obtained a persistent UUID that identified the browser, and persisted between containers and normal/private browsing mode, but not profiles. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR...

Mozilla -- persistent UUID that identifies browser

[email protected] reports: An attacker who enumerated resources from the WebCompat extension could have obtained a persistent UUID that identified the browser, and persisted between containers and normal/private browsing mode, but not profiles. This vulnerability affects Firefox 140, Firefox E...