Security Vulnerabilities fixed in Thunderbird 115.11 — Mozilla

A type check was missing when handling fonts in PDF.js, which would allow arbitrary JavaScript execution in the PDF.js context.
If the browser.privatebrowsing.autostart preference is enabled, IndexedDB files were not properly deleted when the window was closed. This preference is disabled by default in Thunderbird.
A bug in popup notifications’ interaction with WebAuthn made it easier for an attacker to trick a user into granting permissions.
When importing resources using Web Workers, error messages would distinguish the difference between application/javascript responses and non-script responses. This could have been abused to learn information cross-origin.
When saving a page to PDF, certain font styles could have led to a potential use-after-free crash.
Memory safety bugs present in Firefox 125, Firefox ESR 115.10, and Thunderbird 115.10. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.