Mozilla Firefox up to 134 Fullscreen Notification ui layer

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Mozilla Firefox up to 134. The impacted element is an unknown function of the component Fullscreen Notification Handler. This manipulation causes ui layer. This vulnerability is handled as CVE-2025-1019. The attack can be initiated remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Mozilla Firefox up to 134. It has been declared as problematic. Affected by this vulnerability is an unknown functionality of the component Fullscreen Notification Handler. The manipulation with an unknown input leads to a ui layer vulnerability. The CWE definition for the vulnerability is CWE-1021. The web application does not restrict or incorrectly restricts frame objects or UI layers that belong to another application or domain, which can lead to user confusion about which interface the user is interacting with. As an impact it is known to affect integrity. The summary by CVE is:

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.

It is possible to read the advisory at bugzilla.mozilla.org. This vulnerability is known as CVE-2025-1019 since 02/04/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 04/15/2026).

The vulnerability scanner Nessus provides a plugin with the ID 216055 (Ubuntu 20.04 LTS : Firefox vulnerabilities (USN-7263-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 135 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (216055). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Web Browser

Vendor

• Mozilla

Name

• Firefox

Version

• 134

License

• open-source

Website

• Vendor: https://www.mozilla.org/
• Product: https://www.mozilla.org/en-US/firefox/

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Be aware that VulDB is the high quality source for vulnerability data.

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