By tricking the browser with a `X-Frame-Options` header, a sandboxed iframe could have presented a button that, if clicked by a user, would bypass restrictions to open a new window. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.
On Windows 10, when using the 'Save As' functionality, an attacker could have tricked the browser into saving the file with a disallowed extension such as `.url` by including an invalid character in the extension. *Note:* This issue only affected Windows operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.
Offscreen Canvas did not properly track cross-origin tainting, which could be used to access image data from another site in violation of same-origin policy. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.
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 < 126, Firefox ESR < 115.11, and Thunderbird < 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 < 126, Firefox ESR < 115.11, and Thunderbird < 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 < 126, Firefox ESR < 115.11, and Thunderbird < 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 < 126, Firefox ESR < 115.11, and Thunderbird < 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 < 126, Firefox ESR < 115.11, and Thunderbird < 115.11.
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 < 126, Firefox ESR < 115.11, and Thunderbird < 115.11.
There was no limit to the number of HTTP/2 CONTINUATION frames that would be processed. A server could abuse this to create an Out of Memory condition in the browser. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.