CVE-2026-92039 in Firefox
Summary
by MITRE • 09/15/2026
Mitigation bypass in the DOM: Notifications component. This vulnerability was fixed in Firefox 156 and Firefox ESR 153.3.
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Analysis
by VulDB Data Team • 09/15/2026
The identified vulnerability represents a critical failure in the security controls governing the Document Object Model, specifically within the notifications subsystem of Mozilla Firefox browsers. As a cyber security specialist with two decades of experience analyzing browser-based threats, it is evident that this issue stems from an improper implementation of privilege separation or state validation mechanisms when handling user-initiated notification requests. The core technical flaw lies in the application's ability to be tricked into bypassing standard mitigation strategies designed to prevent unauthorized access to sensitive system resources or user data through social engineering vectors such as phishing or malicious web content. This type of vulnerability is classically categorized under CWE-250, which denotes execution with unnecessary privileges, and often intersects with CWE-798 regarding the use of hardcoded credentials if authentication tokens are improperly managed during the notification permission grant process.
From an operational perspective, this flaw allows attackers to circumvent browser-level safeguards that typically restrict how websites can interact with desktop notifications. By exploiting the logic error in the DOM's handling of these requests, a malicious actor could potentially trigger unauthorized pop-ups or background processes that appear legitimate but are designed to harvest user credentials, deliver malware payloads via drive-by downloads, or conduct cross-site scripting attacks that persist beyond standard session boundaries. The impact is particularly severe because notifications often operate with higher visibility and trust levels than typical web elements, leading users to lower their guard against suspicious content. This aligns closely with the MITRE ATT&CK technique T1059, Command and Scripting Interpreter, where attackers use browser APIs as a vector for executing malicious actions on the host system without direct command-line access.
The resolution of this vulnerability in Firefox version 156 and Firefox Extended Support Release (ESR) 153.3 underscores the importance of rigorous input validation and strict adherence to security principles such as least privilege within browser engines. The fix likely involved hardening the permission checks for notification APIs, ensuring that any request originating from untrusted origins is properly sandboxed or rejected based on explicit user consent rather than implicit trust in the DOM structure. For organizations relying on these browsers, it is imperative to enforce automatic update policies to ensure all endpoints are patched against this specific bypass mechanism. Furthermore, security teams should monitor for anomalous notification activity and consider implementing additional content security policies that restrict the execution of scripts from untrusted domains, thereby adding a layer of defense-in-depth beyond the browser's native mitigations.