By using a link with <code>rel="localization"</code> a use-after-free could have been triggered by destroying an object during JavaScript execution and then referencing the object through a freed pointer, leading to a potential exploitable crash. This vulnerability affects Thunderbird < 91.8, Firefox < 99, and Firefox ESR < 91.8.
The sourceMapURL feature in devtools was missing security checks that would have allowed a webpage to attempt to include local files or other files that should have been inaccessible. This vulnerability affects Firefox < 99.
SVG's <code><use></code> element could have been used to load unexpected content that could have executed script in certain circumstances. While the specification seems to allow this, other browsers do not, and web developers relied on this property for script security so gecko's implementation was aligned with theirs. This vulnerability affects Firefox < 99.
When generating the assembly code for <code>MLoadTypedArrayElementHole</code>, an incorrect AliasSet was used. In conjunction with another vulnerability this could have been used for an out of bounds memory read. This vulnerability affects Thunderbird < 91.8, Firefox < 99, and Firefox ESR < 91.8.
If a user installed an extension of a particular type, the extension could have auto-updated itself and while doing so, bypass the prompt which grants the new version the new requested permissions. This vulnerability affects Firefox < 97, Thunderbird < 91.6, and Firefox ESR < 91.6.
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.
Remote Agent, used in WebDriver, did not validate the Host or Origin headers. This could have allowed websites to connect back locally to the user's browser to control it. <br>*This bug only affected Firefox when WebDriver was enabled, which is not the default configuration.*. This vulnerability affects Firefox < 97.
When clicking on a tel: link, USSD codes, specified after a <code>\*</code> character, would be included in the phone number. On certain phones, or on certain carriers, if the number was dialed this could perform actions on a user's account, similar to a cross-site request forgery attack.<br>*This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 97.
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.