By encoding Unicode whitespace characters within the From email header, an attacker can spoof the sender email address that Thunderbird displays. This vulnerability affects Thunderbird < 68.8.0.

When accepting a malicious intent from other installed apps, Firefox for Android accepted manifests from arbitrary file paths and allowed declaring webapp manifests for other origins. This could be used to gain fullscreen access for UI spoofing and could also lead to cross-origin attacks on targeted websites. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 83.

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.

Websites redirecting to a non-HTTP scheme URL could allow a website address to be spoofed for a malicious page This vulnerability affects Firefox for iOS < 136.

Scanning certain QR codes that included text with a website URL could allow the URL to be opened without presenting the user with a confirmation alert first This vulnerability affects Firefox for iOS < 136.

When navigating from inside an iframe while requesting fullscreen access, an attacker-controlled tab could have made the browser unable to leave fullscreen mode. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.

Under certain conditions, Firefox did not display a warning when a user attempted to navigate to a new protocol handler. This vulnerability affects Firefox < 121.

A malicious web site can enter fullscreen mode while simultaneously triggering a WebAuthn prompt. This could have obscured the fullscreen notification and could have been leveraged in a spoofing attack. This vulnerability affects Firefox < 119.

When scanning QR codes, Firefox for Android would have allowed navigation to some URLs that do not point to web content.<br>*This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 96.

Opening Javascript links in a new tab via long-press in the Firefox iOS client could result in a malicious script spoofing the URL of the new tab. This vulnerability affects Firefox for iOS < 134.

Firefox did not reset the address bar after the beforeunload dialog was shown if the user chose to remain on the page. This could have resulted in an incorrect URL being shown when used in conjunction with other unexpected browser behaviors. This vulnerability affects Firefox < 80.

A unicode RTL order character in the downloaded file name can be used to change the file's name during the download UI flow to change the file extension. This vulnerability affects Firefox for iOS < 28.

In multiple cases browser prompts could have been obscured by popups controlled by content. These could have led to potential user confusion and spoofing attacks. This vulnerability affects Firefox < 113, Firefox ESR < 102.11, and Thunderbird < 102.11.

When parsing internationalized domain names, high bits of the characters in the URLs were sometimes stripped, resulting in inconsistencies that could lead to user confusion or attacks such as phishing. This vulnerability affects Firefox < 94.

If a domain name contained a RTL character, it would cause the domain to be rendered to the right of the path. This could lead to user confusion and spoofing attacks. <br>*This bug only affects Firefox for Android. Other operating systems are unaffected.*<br>*Note*: Due to a clerical error this advisory was not included in the original announcement, and was added in Feburary 2022. This vulnerability affects Firefox < 92.

When styling and rendering an oversized `<select>` element, Firefox did not apply correct clipping which allowed an attacker to paint over the user interface. This vulnerability affects Firefox < 89.

Thunderbird did not check if the user ID associated with an OpenPGP key has a valid self signature. An attacker may create a crafted version of an OpenPGP key, by either replacing the original user ID, or by adding another user ID. If Thunderbird imports and accepts the crafted key, the Thunderbird user may falsely conclude that the false user ID belongs to the correspondent. This vulnerability affects Thunderbird < 78.9.1.

A compromised content process could have performed session history manipulations it should not have been able to due to testing infrastructure that was not restricted to testing-only configurations. This vulnerability affects Firefox < 88.

By downloading a file with the .fileloc extension, a semi-privileged extension could launch an arbitrary application on the user's computer. The attacker is restricted as they are unable to download non-quarantined files or supply command line arguments to the application, limiting the impact. Note: this issue only occurs on Mac OSX. Other operating systems are unaffected. This vulnerability affects Thunderbird < 68.5, Firefox < 73, and Firefox < ESR68.5.

Under certain circumstances, navigating to a webpage would result in the address missing from the location URL bar, making it unclear what the URL was for the loaded webpage. This vulnerability affects Firefox for iOS < 133.

Mozilla Firefox before 26.0 and SeaMonkey before 2.23 do not properly consider the sandbox attribute of an IFRAME element during processing of a contained OBJECT element, which allows remote attackers to bypass intended sandbox restrictions via a crafted web site.

The browser could have been confused into transferring a pointer lock state into another tab, which could have lead to clickjacking attacks. This vulnerability affects Firefox < 85.

Malicious websites may have been able to perform user intent confirmation through tapjacking. This could have led to users unknowingly approving the launch of external applications, potentially exposing them to underlying vulnerabilities. This vulnerability affects Firefox < 133 and Thunderbird < 133.

A crafted URL containing Arabic script and whitespace characters could have hidden the true origin of the page, resulting in a potential spoofing attack. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.

Opening an external link to an HTTP website when Firefox iOS was previously closed and had an HTTPS tab open could in some cases result in the padlock icon showing an HTTPS indicator incorrectly This vulnerability affects Firefox for iOS < 131.2.

The black fade animation when exiting fullscreen is roughly the length of the anti-clickjacking delay on permission prompts. It was possible to use this fact to surprise users by luring them to click where the permission grant button would be about to appear. This vulnerability affects Firefox < 120, Firefox ESR < 115.5.0, and Thunderbird < 115.5.

If an attacker needed a user to load an insecure http: page and knew that user had enabled HTTPS-only mode, the attacker could have tricked the user into clicking to grant an HTTPS-only exception if they could get the user to participate in a clicking game. This vulnerability affects Firefox < 120.

The timing of a button click causing a popup to disappear was approximately the same length as the anti-clickjacking delay on permission prompts. It was possible to use this fact to surprise users by luring them to click where the permission grant button would be about to appear. This vulnerability affects Firefox ESR < 115.6 and Firefox < 121.

A select option could partially obscure the confirmation prompt shown before launching external apps. This could be used to trick a user in to launching an external app unexpectedly. *This issue only affects Android versions of Firefox.* This vulnerability affects Firefox < 136.

The permission request prompt from the site in the background tab was overlaid on top of the site in the foreground tab. This vulnerability affects Firefox for iOS < 115.

By manipulating the fullscreen feature while opening a data-list, an attacker could have overlaid a text box over the address bar. This could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 127.

A select option could partially obscure security prompts. This could be used by a malicious site to trick a user into granting permissions. *This issue only affects Android versions of Firefox.* This vulnerability affects Firefox < 129.

A background script invoking <code>requestFullscreen</code> and then blocking the main thread could force the browser into fullscreen mode indefinitely, resulting in potential user confusion or spoofing attacks. This vulnerability affects Firefox < 110, Thunderbird < 102.8, and Firefox ESR < 102.8.

A clickjacking vulnerability could have been used to trick a user into leaking saved payment card details to a malicious page. This vulnerability affects Firefox < 139, Firefox ESR < 128.11, Thunderbird < 139, and Thunderbird < 128.11.

Data was not properly sanitized when decoding a QUIC ACK frame; this could have led to unrestricted memory consumption and a crash. This vulnerability affects Firefox < 124.

When following a link that opened an intent://-schemed URL, causing a custom tab to be opened, Firefox for Android could be tricked into displaying the incorrect URI. <br> *Note: This issue only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox ESR < 68.7.

Use tables inside of an iframe, an attacker could have caused iframe contents to be rendered outside the boundaries of the iframe, resulting in potential user confusion or spoofing attacks. This vulnerability affects Firefox ESR < 102.5, Thunderbird < 102.5, and Firefox < 107.

Service Workers did not detect Private Browsing Mode correctly in all cases, which could have led to Service Workers being written to disk for websites visited in Private Browsing Mode. This would not have persisted them in a state where they would run again, but it would have leaked Private Browsing Mode details to disk. This vulnerability affects Firefox < 107.

If a custom mouse cursor is specified in CSS, under certain circumstances the cursor could have been drawn over the browser UI, resulting in potential user confusion or spoofing attacks. This vulnerability affects Firefox ESR < 102.5, Thunderbird < 102.5, and Firefox < 107.

A malicious website could have used a combination of exiting fullscreen mode and `requestPointerLock` to cause the user's mouse to be re-positioned unexpectedly, which could have led to user confusion and inadvertently granting permissions they did not intend to grant. This vulnerability affects Firefox < 123, Firefox ESR < 115.8, and Thunderbird < 115.8.

When combining CSS properties for overflow and transform, the mouse cursor could interact with different coordinates than displayed. This vulnerability affects Firefox ESR < 102.1, Firefox ESR < 91.12, Firefox < 103, Thunderbird < 102.1, and Thunderbird < 91.12.

An improper implementation of the new iframe sandbox keyword <code>allow-top-navigation-by-user-activation</code> could lead to script execution without <code>allow-scripts</code> being present. This vulnerability affects Thunderbird < 91.9, Firefox ESR < 91.9, and Firefox < 100.

When reusing existing popups Firefox would have allowed them to cover the fullscreen notification UI, which could have enabled browser spoofing attacks. This vulnerability affects Thunderbird < 91.9, Firefox ESR < 91.9, and Firefox < 100.

Due to a layout change, iframe contents could have been rendered outside of its border. This could have led to user confusion or spoofing attacks. This vulnerability affects Thunderbird < 91.8, Firefox < 99, and Firefox ESR < 91.8.

Mozilla Firefox before 27.0 and SeaMonkey before 2.24 allow remote attackers to bypass the Same Origin Policy and obtain sensitive information by using an IFRAME element in conjunction with certain timing measurements involving the document.caretPositionFromPoint and document.elementFromPoint functions.

Cross-origin iframes that contained a login form could have been recognized by the login autofill service, and populated. This could have been used in clickjacking attacks, as well as be read across partitions in dynamic first party isolation. This vulnerability affects Firefox < 83.

The file-download implementation in Mozilla Firefox before 27.0 and SeaMonkey before 2.24 does not properly restrict the timing of button selections, which allows remote attackers to conduct clickjacking attacks, and trigger unintended launching of a downloaded file, via a crafted web site.

When the RSS Feed preview about:feeds page is framed within another page, it can be used in concert with scripted content for a clickjacking attack that confuses users into downloading and executing an executable file from a temporary directory. *Note: This issue only affects Windows operating systems. Other operating systems are not affected.*. This vulnerability affects Firefox < 64.

Using object or embed tags, it was possible to frame other websites, even if they disallowed framing using the X-Frame-Options header. This vulnerability affects Thunderbird < 78 and Firefox < 78.0.2.

The fullscreen notification is prematurely hidden when fullscreen is re-requested quickly by the user. This could have been leveraged to perform a potential spoofing attack. This vulnerability affects Firefox < 135 and Thunderbird < 135.