Security Vulnerabilities fixed in Firefox ESR 115.15 — Mozilla

A potentially exploitable type confusion could be triggered when looking up a property name on an object being used as the with environment.
Internal browser event interfaces were exposed to web content when privileged EventHandler listener callbacks ran for those events. Web content that tried to use those interfaces would not be able to use them with elevated privileges, but their presence would indicate certain browser features had been used, such as when a user opened the Dev Tools console.
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.
The JavaScript garbage collector could mis-color cross-compartment objects if OOM conditions were detected at the right point between two passes. This could have led to memory corruption.