A type check was missing when handling fonts in PDF.js, which would allow arbitrary JavaScript execution in the PDF.js context. This vulnerability affects Firefox less than 126, Firefox ESR less than 115.11, and Thunderbird less than 115.11. 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 Firefox. This vulnerability affects Firefox less than 126, Firefox ESR less than 115.11, and Thunderbird less than 115.11. A bug in popup notifications' interaction with WebAuthn made it easier for an attacker to trick a user into granting permissions. This vulnerability affects Firefox less than 126, Firefox ESR less than 115.11, and Thunderbird less than 115.11. 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. This vulnerability affects Firefox less than 126, Firefox ESR less than 115.11, and Thunderbird less than 115.11. When saving a page to PDF, certain font styles could have led to a potential use-after-free crash. This vulnerability affects Firefox less than 126, Firefox ESR less than 115.11, and Thunderbird less than 115.11. 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. This vulnerability affects Firefox less than 126, Firefox ESR less than 115.11, and Thunderbird less than 115.11