Mozilla » Firefox : Security Vulnerabilities, CVEs, (XSS) CVSS score >= 1

When opening a page in reader mode, the redirect URL could have caused attacker-controlled script to execute in a reflected Cross-Site Scripting (XSS) attack. This vulnerability affects Firefox for iOS < 119.

Cross-Site Tracing occurs when a server will echo a request back via the Trace method, allowing an XSS attack to access to authorization headers and cookies inaccessible to JavaScript (such as cookies protected by HTTPOnly). To mitigate this attack, browsers placed limits on <code>fetch()</code> and XMLHttpRequest; however some webservers have implemented non-standard headers such as <code>X-Http-Method-Override</code> that override the HTTP method, and made this attack possible again. Thunderbird has applied the same mitigations to the use of this and similar headers. This vulnerability affects Firefox ESR < 102.5, Thunderbird < 102.5, and Firefox < 107.

When injecting an HTML base element, some requests would ignore the CSP's base-uri settings and accept the injected element's base instead. This vulnerability affects Firefox ESR < 102.3, Thunderbird < 102.3, and Firefox < 105.

SVG <code>&lt;use&gt;</code> tags that referenced a same-origin document could have resulted in script execution if attacker input was sanitized via the HTML Sanitizer API. This would have required the attacker to reference a same-origin JavaScript file containing the script to be executed. This vulnerability affects Firefox < 102.

The HTML Sanitizer should have sanitized the <code>href</code> attribute of SVG <code>&lt;use&gt;</code> tags; however it incorrectly did not sanitize <code>xlink:href</code> attributes. This vulnerability affects Firefox < 102.

Firefox's HTML parser did not correctly interpret HTML comment tags, resulting in an incongruity with other browsers. This could have been used to escape HTML comments on pages that put user-controlled data in them. This vulnerability affects Firefox < 101.

When receiving a URL through a SEND intent, Firefox would have searched for the text, but subsequent usages of the address bar might have caused the URL to load unintentionally, which could lead to XSS and spoofing attacks. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 95.

Documents loaded with the CSP sandbox directive could have escaped the sandbox's script restriction by embedding additional content. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

A Universal XSS vulnerability was present in Firefox for Android resulting from improper sanitization when processing a URL scanned from a QR code. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 94.

A malicious webpage could have forced a Firefox for Android user into executing attacker-controlled JavaScript in the context of another domain, resulting in a Universal Cross-Site Scripting vulnerability. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected. Further details are being temporarily withheld to allow users an opportunity to update.*. This vulnerability affects Firefox < 88.0.1 and Firefox for Android < 88.1.3.

Lack of escaping allowed HTML injection when a webpage was viewed in Reader View. While a Content Security Policy prevents direct code execution, HTML injection is still possible. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 88.

An XSS bug in internal error pages could have led to various spoofing attacks, including other error pages and the address bar. Note: This issue only affected Firefox for Android. Other operating systems are unaffected. This vulnerability affects Firefox < 85.

Firefox did not block execution of scripts with incorrect MIME types when the response was intercepted and cached through a ServiceWorker. This could lead to a cross-site script inclusion vulnerability, or a Content Security Policy bypass. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

A parsing and event loading mismatch in Firefox's SVG code could have allowed load events to fire, even after sanitization. An attacker already capable of exploiting an XSS vulnerability in privileged internal pages could have used this attack to bypass our built-in sanitizer. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

Firefox sometimes ran the onload handler for SVG elements that the DOM sanitizer decided to remove, resulting in JavaScript being executed after pasting attacker-controlled data into a contenteditable element. This vulnerability affects Firefox < 81, Thunderbird < 78.3, and Firefox ESR < 78.3.

For native-to-JS bridging the app requires a unique token to be passed that ensures non-app code can't call the bridging functions. That token could leak when used for downloading files. This vulnerability affects Firefox for iOS < 26.

If a template tag was used in a select tag, the parser could be confused and allow JavaScript parsing and execution when it should not be allowed. A site that relied on the browser behaving correctly could suffer a cross-site scripting vulnerability as a result. In general, this flaw cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but is potentially a risk in browser or browser-like contexts. This vulnerability affects Thunderbird < 68.5, Firefox < 73, and Firefox < ESR68.5.

When pasting a &lt;style&gt; tag from the clipboard into a rich text editor, the CSS sanitizer does not escape &lt; and &gt; characters. Because the resulting string is pasted directly into the text node of the element this does not result in a direct injection into the webpage; however, if a webpage subsequently copies the node's innerHTML, assigning it to another innerHTML, this would result in an XSS vulnerability. Two WYSIWYG editors were identified with this behavior, more may exist. This vulnerability affects Firefox ESR < 68.4 and Firefox < 72.

When pasting a &lt;style&gt; tag from the clipboard into a rich text editor, the CSS sanitizer incorrectly rewrites a @namespace rule. This could allow for injection into certain types of websites resulting in data exfiltration. This vulnerability affects Firefox ESR < 68.4 and Firefox < 72.

Scanning a QR code that contained a javascript: URL would have resulted in the Javascript being executed.

A Content-Security-Policy that blocks in-line scripts could be bypassed using an object tag to execute JavaScript in the protected document (cross-site scripting). This is a separate bypass from CVE-2019-17000.*Note: This flaw only affected Firefox 69 and was not present in earlier versions.*. This vulnerability affects Firefox < 70.

An object tag with a data URI did not correctly inherit the document's Content Security Policy. This allowed a CSP bypass in a cross-origin frame if the document's policy explicitly allowed data: URIs. This vulnerability affects Firefox < 70.

Failure to correctly handle null bytes when processing HTML entities resulted in Firefox incorrectly parsing these entities. This could have led to HTML comment text being treated as HTML which could have led to XSS in a web application under certain conditions. It could have also led to HTML entities being masked from filters - enabling the use of entities to mask the actual characters of interest from filters. This vulnerability affects Firefox < 70, Thunderbird < 68.2, and Firefox ESR < 68.2.

Some HTML elements, such as &lt;title&gt; and &lt;textarea&gt;, can contain literal angle brackets without treating them as markup. It is possible to pass a literal closing tag to .innerHTML on these elements, and subsequent content after that will be parsed as if it were outside the tag. This can lead to XSS if a site does not filter user input as strictly for these elements as it does for other elements. This vulnerability affects Firefox < 69, Thunderbird < 68.1, Thunderbird < 60.9, Firefox ESR < 60.9, and Firefox ESR < 68.1.