Under certain circumstances, a user opt-in setting that Focus should require authentication before use could have been be bypassed (distinct from CVE-2025-0245). This vulnerability was fixed in Firefox 136.

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

Different techniques existed to obscure the fullscreen notification in Firefox and Focus for Android. These could have led to potential user confusion and spoofing attacks. *This bug only affects Firefox and Focus for Android. Other versions of Firefox are unaffected.* This vulnerability affects Firefox for Android < 112 and Focus for Android < 112.

Same-origin policy bypass in the DOM: Networking component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

After downloading a Windows <code>.url</code> shortcut from the local filesystem, an attacker could supply a remote path that would lead to unexpected network requests from the operating system. This also had the potential to leak NTLM credentials to the resource.<br>*This bug only affects Firefox on Windows. Other operating systems are unaffected.*. This vulnerability affects Firefox < 110, Thunderbird < 102.8, and Firefox ESR < 102.8.

Same-origin policy bypass in the DOM: Notifications component. This vulnerability was fixed in Firefox 145, Firefox ESR 140.5, Thunderbird 145, and Thunderbird 140.5.

The Firefox and Firefox Focus UI for the Android custom tab feature only showed the "site" that was loaded, not the full hostname. User supplied content hosted on a subdomain of a site could have been used to fool a user into thinking it was content from a different subdomain of that site. This vulnerability was fixed in Firefox 144.

Spoofing issue in the Site Permissions component. This vulnerability was fixed in Firefox 143 and Thunderbird 143.

Undefined behavior in the Audio/Video component. This vulnerability was fixed in Firefox 149 and Thunderbird 149.

Undefined behavior in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

If a Thunderbird user quoted from an HTML email, for example by replying to the email, and the email contained either a VIDEO tag with the POSTER attribute or an OBJECT tag with a DATA attribute, a network request to the referenced remote URL was performed, regardless of a configuration to block remote content. An image loaded from the POSTER attribute was shown in the composer window. These issues could have given an attacker additional capabilities when targetting releases that did not yet have a fix for CVE-2022-3033 which was reported around three months ago. This vulnerability affects Thunderbird < 102.5.1.

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.

The date picker could partially obscure security prompts. This could be used by a malicious site to trick a user into granting permissions. This vulnerability affects Firefox < 129, Firefox ESR < 115.14, Firefox ESR < 128.1, Thunderbird < 128.1, and Thunderbird < 115.14.

When a TLS Certificate error occurs on a domain protected by the HSTS header, the browser should not allow the user to bypass the certificate error. On Firefox for Android, the user was presented with the option to bypass the error; this could only have been done by the user explicitly. <br>*This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 102.

If a Thunderbird user replied to a crafted HTML email containing a <code>meta</code> tag, with the <code>meta</code> tag having the <code>http-equiv="refresh"</code> attribute, and the content attribute specifying an URL, then Thunderbird started a network request to that URL, regardless of the configuration to block remote content. In combination with certain other HTML elements and attributes in the email, it was possible to execute JavaScript code included in the message in the context of the message compose document. The JavaScript code was able to perform actions including, but probably not limited to, read and modify the contents of the message compose document, including the quoted original message, which could potentially contain the decrypted plaintext of encrypted data in the crafted email. The contents could then be transmitted to the network, either to the URL specified in the META refresh tag, or to a different URL, as the JavaScript code could modify the URL specified in the document. This bug doesn't affect users who have changed the default Message Body display setting to 'simple html' or 'plain text'. This vulnerability affects Thunderbird < 102.2.1 and Thunderbird < 91.13.1.

Setting a nameless cookie with an equals sign in the value shadowed other cookies. Even if the nameless cookie was set over HTTP and the shadowed cookie included the `Secure` attribute. This vulnerability was fixed in Firefox 141, Firefox ESR 140.1, Thunderbird 141, and Thunderbird 140.1.

A same-origin policy violation could have allowed the theft of cross-origin URL entries, leaking the result of a redirect, via `performance.getEntries()`. This vulnerability affects Firefox < 106, Firefox ESR < 102.4, and Thunderbird < 102.4.

Web application manifests were stored by using an insecure MD5 hash which allowed for a hash collision to overwrite another application's manifest. This could have been exploited to run arbitrary code in another application's context. *This issue only affects Firefox for Android. Other versions of Firefox are unaffected.* This vulnerability affects Firefox < 126.

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 is a different issue from CVE-2020-26954 and only affected Firefox for Android. Other operating systems are unaffected. This vulnerability affects Firefox < 86.

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 147, Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

Same-origin policy bypass in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 142, Firefox ESR 115.27, Firefox ESR 128.14, Firefox ESR 140.2, Thunderbird 142, Thunderbird 128.14, and Thunderbird 140.2.

Thunderbird cached CORS preflight responses across IP address changes. This allowed circumventing CORS with DNS rebinding. This vulnerability was fixed in Firefox 141, Firefox ESR 140.1, Thunderbird 141, and Thunderbird 140.1.

Thunderbird executed `javascript:` URLs when used in `object` and `embed` tags. This vulnerability was fixed in Firefox 141, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.

In some cases search terms persisted in the URL bar even after navigating away from the search page. This vulnerability was fixed in Firefox 141, Firefox ESR 140.1, Thunderbird 141, and Thunderbird 140.1.

XSLT document loading did not correctly propagate the source document which bypassed its CSP. This vulnerability was fixed in Firefox 141, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.

Insufficient escaping in the “Copy as cURL” feature could potentially be used to trick a user into executing unexpected code. This vulnerability was fixed in Firefox 141, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.

An attacker was able to bypass the `connect-src` directive of a Content Security Policy by manipulating subdocuments. This would have also hidden the connections from the Network tab in Devtools. This vulnerability was fixed in Firefox 140 and Thunderbird 140.

The QR scanner could allow arbitrary websites to be opened if a user was tricked into scanning a malicious link that leveraged Firefox's open-text URL scheme. This vulnerability was fixed in Firefox for iOS 141.

Multiple unspecified vulnerabilities in Mozilla Firefox have unspecified vectors and impact, as claimed during ToorCon 2006. NOTE: the vendor and original researchers have released a follow-up comment disputing this issue, in which one researcher states that "I have no undisclosed Firefox vulnerabilities. The person who was speaking with me made this claim, and I honestly have no idea if he has them or not.

A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document's process instead of the intended frame, potentially enabling a sandbox escape. This vulnerability was fixed in Firefox 138, Firefox ESR 128.10, Firefox ESR 115.23, Thunderbird 138, and Thunderbird 128.10.

Firefox incorrectly accepted a newline in a HTTP/3 header, interpretting it as two separate headers. This allowed for a header splitting attack against servers using HTTP/3. This vulnerability affects Firefox < 91.0.1 and Thunderbird < 91.0.1.

Thunderbird's handling of the X-Mozilla-External-Attachment-URL header can be exploited to execute JavaScript in the file:/// context. By crafting a nested email attachment (message/rfc822) and setting its content type to application/pdf, Thunderbird may incorrectly render it as HTML when opened, allowing the embedded JavaScript to run without requiring a file download. This behavior relies on Thunderbird auto-saving the attachment to /tmp and linking to it via the file:/// protocol, potentially enabling JavaScript execution as part of the HTML. This vulnerability was fixed in Thunderbird 128.10.1 and Thunderbird 138.0.1.

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.

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.

Focus was incorrectly allowing internal links to utilize the app scheme used for deeplinking, which could result in links potentially circumventing some URL safety checks This vulnerability affects Focus for iOS < 132.

Same-origin policy bypass in the DOM: Workers component. This vulnerability was fixed in Firefox 145, Firefox ESR 140.5, Thunderbird 145, and Thunderbird 140.5.

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 145, Firefox ESR 140.5, Thunderbird 145, and Thunderbird 140.5.

Insufficient escaping in the “Copy as cURL” feature could have been used to trick a user into executing unexpected code on Windows. This did not affect the application when running on other operating systems. This vulnerability was fixed in Firefox 144, Firefox ESR 140.4, Thunderbird 144, and Thunderbird 140.4.

When switching between Android apps using the card carousel Firefox shows a black screen as its card image when a password-related screen was the last one being used. Prior to Firefox 144 the password edit screen was visible. This vulnerability was fixed in Firefox 144.

When constructing a permission prompt for WebRTC, a URI was supplied from the content process. This URI was untrusted, and could have been the URI of an origin that was previously granted permission; bypassing the prompt. This vulnerability affects Firefox < 78.

When "%2F" was present in a manifest URL, Firefox's AppCache behavior may have become confused and allowed a manifest to be served from a subdirectory. This could cause the appcache to be used to service requests for the top level directory. This vulnerability affects Firefox < 78.

Incorrect boundary conditions in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 145 and Thunderbird 145.

A potentially exploitable crash in "EnumerateSubDocuments" while adding or removing sub-documents. This vulnerability affects Firefox ESR < 45.6 and Thunderbird < 45.6.

The lockscreen feature in Mozilla Firefox OS before 2.5 does not properly restrict failed authentication attempts, which makes it easier for physically proximate attackers to obtain access by entering many passcode guesses.

If a specific sequence of actions is performed when opening a new tab, the triggering principal associated with the new tab may have been incorrect. The triggering principal is used to calculate many values, including the `Referer` and `Sec-*` headers, meaning there is the potential for incorrect security checks within the browser in addition to incorrect or misleading information sent to remote websites. *This bug only affects Firefox for Android. Other versions of Firefox are unaffected.* This vulnerability affects Firefox < 127.

Documents in deeply-nested cross-origin browsing contexts could have obtained permissions granted to the top-level origin, bypassing the existing prompt and wrongfully inheriting the top-level permissions. This vulnerability affects Thunderbird < 91.9, Firefox ESR < 91.9, and Firefox < 100.

The mozilla::a11y::HyperTextAccessible::GetChildOffset function in the accessibility implementation in Mozilla Firefox before 49.0 allows remote attackers to execute arbitrary code via a crafted web site.

A compromised content process could send a message to the parent process that would cause the 'Click to Play' permission prompt to be shown. However, due to lack of validation from the parent process, if the user accepted the permission request an attacker-controlled permission would be granted rather than the 'Click to Play' permission. This vulnerability affects Firefox < 70.

Mozilla Firefox before 47.0 allows remote attackers to bypass the Same Origin Policy and modify the location.host property via an invalid data: URL.