Security Vulnerabilities fixed in Thunderbird 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.
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.