In addition to detecting when a user was taking a screenshot (XXX), a website was able to overlay the 'My Shots' button that appeared, and direct the user to a replica Firefox Screenshots page that could be used for phishing. This vulnerability affects Firefox < 127.

An attacker could have positioned a `datalist` element to obscure the address bar. This vulnerability affects Firefox < 113, Firefox ESR < 102.11, and Thunderbird < 102.11.

By displaying a form validity message in the correct location at the same time as a permission prompt (such as for geolocation), the validity message could have obscured the prompt, resulting in the user potentially being tricked into granting the permission. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

A website could have obscured the fullscreen notification by using a combination of <code>window.open</code>, fullscreen requests, <code>window.name</code> assignments, and <code>setInterval</code> calls. This could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 112, Focus for Android < 112, Firefox ESR < 102.10, Firefox for Android < 112, and Thunderbird < 102.10.

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

The fullscreen notification could have been hidden on Firefox for Android by using download popups, resulting in potential user confusion or spoofing attacks. <br>*This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 111.

By displaying a prompt with a long description, the fullscreen notification could have been hidden, resulting in potential user confusion or spoofing attacks. <br>*This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 111.

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 was fixed in Firefox for iOS 134.

Different techniques existed to obscure the fullscreen notification in Firefox for Android. These could have led to potential user confusion and spoofing attacks. *This bug only affects Firefox for Android. Other versions of Firefox are unaffected.* This vulnerability affects Firefox < 126.

The exception page for the HTTPS-Only feature, displayed when a website is opened via HTTP, lacked an anti-clickjacking delay, potentially allowing an attacker to trick a user into granting an exception and loading a webpage over HTTP. This vulnerability was fixed in Firefox 140 and Thunderbird 140.

When loading a script with Subresource Integrity, attackers with an injection capability could trigger the reuse of previously cached entries with incorrect, different integrity metadata. This vulnerability affects Firefox < 103.

If upgrade-insecure-requests was specified in the Content Security Policy, and a link was dragged and dropped from that page, the link was not upgraded to https. This vulnerability affects Firefox < 70.

Due to an unusual sequence of attacker-controlled events, a Javascript alert() dialog with arbitrary (although unstyled) contents could be displayed over top an uncontrolled webpage of the attacker's choosing. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

In certain scenarios a malicious website could attempt to display a fake location URL bar which could mislead users as to the actual website address This vulnerability affects Firefox for iOS < 127.

Address bar search suggestions in private browsing mode were re-using session data from normal mode. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 89.

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.

An attacker could cause a select dropdown to be shown over another tab; this could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.

Opening maliciously-crafted URLs in Firefox from other apps such as Safari could have allowed attackers to spoof website addresses if the URLs utilized non-HTTP schemes used internally by the Firefox iOS client. This vulnerability was fixed in Firefox for iOS 139.

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.

If a MIME encoded email contains an OpenPGP inline signed or encrypted message part, but also contains an additional unprotected part, Thunderbird did not indicate that only parts of the message are protected. This vulnerability affects Thunderbird < 78.10.2.

When network partitioning was enabled, e.g. as a result of Enhanced Tracking Protection settings, a TLS error page would allow the user to override an error on a domain which had specified HTTP Strict Transport Security (which implies that the error should not be override-able.) This issue did not affect the network connections, and they were correctly upgraded to HTTPS automatically. This vulnerability affects Firefox < 90.

When viewing an email message A, which contains an attached message B, where B is encrypted or digitally signed or both, Thunderbird may show an incorrect encryption or signature status. After opening and viewing the attached message B, when returning to the display of message A, the message A might be shown with the security status of message B. This vulnerability affects Thunderbird < 91.9.

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.

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.

When sharing geolocation during an active WebRTC share, Firefox could have reset the webRTC sharing state in the user interface, leading to loss of control over the currently granted permission. This vulnerability affects Firefox < 85.

Malicious scripts could display attacker-controlled web content under spoofed domains in Focus for iOS by stalling a _self navigation to an invalid port and triggering an iframe redirect, causing the UI to display a trusted domain without user interaction. This vulnerability was fixed in Focus for iOS 148.2.

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 was fixed in Firefox for iOS 136.

A website could have obscured the fullscreen notification by using a dropdown select input element. This could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 123, Firefox ESR < 115.8, and Thunderbird < 115.8.

The incorrect domain may have been displayed in the address bar during an interrupted navigation attempt. This could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 133 and Thunderbird < 133.

The z-order of the browser windows could be manipulated to hide the fullscreen notification. This could potentially be leveraged to perform a spoofing attack. This vulnerability was fixed in Firefox 135 and Thunderbird 135.

A crafted URL using a blob: URI could have hidden the true origin of the page, resulting in a potential spoofing attack. *Note: This issue only affected Android operating systems. Other operating systems are unaffected.*. This vulnerability was fixed in Firefox 141.

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.

After a website had entered fullscreen mode, it could have used a previously opened popup to obscure the notification that indicates the browser is in fullscreen mode. Combined with spoofing the browser chrome, this could have led to confusing the user about the current origin of the page and credential theft or other attacks. This vulnerability affects Firefox < 74.

By misusing a race in our notification code, an attacker could have forcefully hidden the notification for pages that had received full screen and pointer lock access, which could have been used for spoofing attacks. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

It was possible to cause the browser to enter fullscreen mode without displaying the security UI; thus making it possible to attempt a phishing attack or otherwise confuse the user. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

Multiple prompts and panels from both Firefox and the Android OS could be used to obscure the notification announcing the transition to fullscreen mode after the fix for CVE-2023-6870 in Firefox 121. This could lead to spoofing the browser UI if the sudden appearance of the prompt distracted the user from noticing the visual transition happening behind the prompt. These notifications now use the Android Toast feature. *This bug only affects Firefox on Android. Other operating systems are unaffected.* This vulnerability affects Firefox < 130.

When a URL was provided in a link querystring parameter, Firefox for Android would follow that URL instead of the correct URL, potentially leading to phishing attacks. *This bug only affects Firefox for Android. Other versions of Firefox are unaffected.*. This vulnerability was fixed in Firefox 140.

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.

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.

The frame iterator could get stuck in a loop when encountering certain wasm frames leading to incorrect stack traces. This vulnerability affects Firefox < 128 and Thunderbird < 128.

By navigating a tab using the history API, an attacker could cause the address bar to display the incorrect domain (with the https:// scheme, a blocked port number such as '1', and without a lock icon) while controlling the page contents. This vulnerability affects Firefox < 70.

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.

A phishing site could have repurposed an `about:` dialog to show phishing content with an incorrect origin in the address bar. This vulnerability affects Firefox < 122 and Thunderbird < 115.7.

A compromised content process could have updated the document URI. This could have allowed an attacker to set an arbitrary URI in the address bar or history. This vulnerability affects Firefox < 122.

It was possible for certain browser prompts and dialogs to be activated or dismissed unintentionally by the user due to an incorrect timestamp used to prevent input after page load. This vulnerability affects Firefox < 122, Firefox ESR < 115.7, and Thunderbird < 115.7.

Applications which spawn a Toast notification in a background thread may have obscured fullscreen notifications displayed by Firefox. *This issue only affects Android versions of Firefox and Firefox Focus.* This vulnerability affects Firefox < 121.

In some instances, the user-agent would allow push requests which lacked a valid VAPID even though the push manager subscription defined one. This could allow empty messages to be sent from unauthorized parties. *This bug only affects Firefox on Android.* This vulnerability affects Firefox < 121.

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 website could have obscured the full screen notification by using the file open dialog. This could have led to user confusion and possible spoofing attacks. *Note: This issue only affected macOS operating systems. Other operating systems are unaffected.* This vulnerability affects Firefox < 119, Firefox ESR < 115.4, and Thunderbird < 115.4.1.

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.