#firefox

By using XSL Transforms, a malicious webserver could have served a user an XSL document that would continue to execute JavaScript (within the bounds of the same-origin policy) even after the tab was closed. This vulnerability affects Firefox < 97.

If a user was convinced to drag and drop an image to their desktop or other folder, the resulting object could have been changed into an executable script which would have run arbitrary code after the user clicked on it. This vulnerability affects Firefox < 97, Thunderbird < 91.6, and Firefox ESR < 91.6.

In unusual circumstances, an individual thread may outlive the thread's manager during shutdown. This could have led to a use-after-free causing a potentially exploitable crash. This vulnerability affects Firefox < 98.

Previously Firefox for macOS and Linux would download temporary files to a user-specific directory in <code>/tmp</code>, but this behavior was changed to download them to <code>/tmp</code> where they could be affected by other local users. This behavior was reverted to the original, user-specific directory. <br>*This bug only affects Firefox for macOS and Linux. Other operating systems are unaffected.*. This vulnerability affects Firefox ESR < 91.7 and Thunderbird < 91.7.

When resizing a popup after requesting fullscreen access, the popup would not display the fullscreen notification. This vulnerability affects Firefox < 98, Firefox ESR < 91.7, and Thunderbird < 91.7.

Web-accessible extension pages (pages with a moz-extension:// scheme) were not correctly enforcing the frame-ancestors directive when it was used in the Web Extension's Content Security Policy. This vulnerability affects Firefox < 97, Thunderbird < 91.6, and Firefox ESR < 91.6.

If a document created a sandboxed iframe without <code>allow-scripts</code>, and subsequently appended an element to the iframe's document that e.g. had a JavaScript event handler - the event handler would have run despite the iframe's sandbox. This vulnerability affects Firefox < 97, Thunderbird < 91.6, and Firefox ESR < 91.6.

Mozilla developers Kershaw Chang, Ryan VanderMeulen, and Randell Jesup reported memory safety bugs present in Firefox 97. 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 < 98.

When importing resources using Web Workers, error messages would distinguish the difference between <code>application/javascript</code> responses and non-script responses. This could have been abused to learn information cross-origin. This vulnerability affects Firefox < 97, Thunderbird < 91.6, and Firefox ESR < 91.6.

Under certain circumstances, a JavaScript alert (or prompt) could have been shown while another website was displayed underneath it. This could have been abused to trick the user. <br>*This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 97.