CVE-2026-74951 in Firefox
Summary
by MITRE • 08/18/2026
Clickjacking issue in Firefox for Android. This vulnerability was fixed in Firefox 154.
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Analysis
by VulDB Data Team • 08/18/2026
The identified security flaw represents a classic clickjacking vulnerability within the Mozilla Firefox browser engine as deployed on the Android operating system platform. Clickjacking, formally categorized under CWE-1021 Improper Restriction of Rendered UIs or Frames, is an attack technique that involves embedding a malicious webpage inside an invisible or transparent iframe overlaying a legitimate target site. The core technical failure lies in the browser's handling of frame-busting scripts and security headers such as X-Frame-Options or Content-Security-Policy with frame-ancestors directives. In this specific instance, Firefox for Android failed to properly enforce these restrictions when rendering content from untrusted sources within iframes. This deficiency allows an attacker to construct a deceptive user interface where the victim interacts with what appears to be one set of buttons or links, while their clicks are actually directed at hidden elements on the underlying legitimate website.
The operational impact of this vulnerability is significant because it undermines the principle of least privilege and user intent in web interactions. By exploiting the lack of proper frame isolation, an attacker can trick users into performing unintended actions such as changing account settings, making unauthorized financial transactions, or posting malicious content without their knowledge. This type of attack relies heavily on social engineering to lure victims into visiting a compromised page that contains the malicious iframe payload. The success of the exploit depends on the victim's interaction with the overlaying interface, which masks the true destination of the click events. Because Firefox for Android is widely used mobile browser, this vulnerability affects a substantial user base potentially exposed to phishing and fraud campaigns leveraging this technique.
From an offensive security perspective aligned with MITRE ATT&CK frameworks, this flaw facilitates techniques associated with UI Redressing (T1624) which falls under the broader category of Defense Evasion or Initial Access depending on the context of deployment. The attacker utilizes the browser's rendering engine to bypass visual cues that would normally alert a user to malicious activity. This creates an environment where authentication tokens, session cookies, and other sensitive data can be exfiltrated if combined with cross-site scripting vulnerabilities or simply by forcing actions within authenticated sessions. The absence of robust frame protection mechanisms in this specific version allows the attack vector to remain viable against users who may not recognize subtle discrepancies between their intended action and the actual executed command due to the visual deception employed.
Mitigation strategies for this vulnerability primarily involve ensuring that all clients are updated to Firefox 154 or later, where the underlying rendering engine has been patched to correctly enforce frame-busting logic. For developers integrating content into web applications, it is critical to implement comprehensive Content-Security-Policy headers specifically targeting frame-ancestors to restrict which origins can embed their pages in iframes. Additionally, employing X-Frame-Options with a DENY or SAMEORIGIN value provides an additional layer of defense against clickjacking attempts. Security teams should also monitor for unusual patterns of user interaction that might indicate automated clicking behavior consistent with UI redressing attacks and ensure that multi-factor authentication is enabled to mitigate the impact if such social engineering efforts succeed despite technical controls.