CVE-2026-92030 in Firefox
Summary
by MITRE • 09/15/2026
Mitigation bypass in the DOM: Copy & Paste and Drag & Drop component. This vulnerability was fixed in Firefox 156, Firefox ESR 140.16, 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 browser's security model regarding content manipulation within the Document Object Model, specifically affecting the Copy & Paste and Drag & Drop components. This flaw allows an attacker to bypass intended mitigation mechanisms that are designed to restrict how data is transferred between different contexts or origins. By exploiting this weakness, malicious scripts can manipulate clipboard operations or drag-and-drop events in ways that circumvent standard security checks, potentially leading to unauthorized access to sensitive user data or the execution of unintended actions within a web application's context.
From a technical perspective, the vulnerability stems from improper validation or sanitization logic during the handling of copy and paste events as well as drag-and-drop interactions. These components are fundamental to user interaction but also serve as vectors for cross-site scripting attacks if not properly secured. The browser failed to adequately enforce restrictions on what data could be inserted into the DOM through these methods, allowing malicious payloads to persist or execute despite existing safeguards. This indicates a gap in the implementation of security policies that govern content injection and manipulation via user-initiated actions rather than direct script execution alone.
The operational impact of this vulnerability is significant for users relying on Firefox-based browsers for secure web interactions. Attackers could leverage this flaw to steal sensitive information such as passwords, credit card numbers, or personal identification details stored in clipboard buffers or transferred through drag-and-drop operations between tabs or windows. Furthermore, it enables sophisticated phishing attacks where malicious content appears legitimate due to the bypass of security warnings or restrictions associated with pasted data. This undermines user trust and compromises the integrity of web applications that depend on secure input handling mechanisms.
This issue aligns closely with CWE-79, which covers Cross-site Scripting vulnerabilities, particularly those involving DOM-based injection through event handlers like paste or drop. It also relates to ATT&CK technique T1059, Command and Scripting Interpreter, as the bypass allows for potential execution of malicious code within the browser environment by circumventing content security policies or same-origin restrictions that typically limit such activities. The ability to manipulate DOM elements via clipboard operations effectively expands the attack surface beyond traditional script injection points.
Mitigation has been addressed in Firefox version 156 and extended support releases including ESR versions 140.16 and 153.3, indicating a comprehensive fix across both current development branches and long-term support channels. Users are strongly advised to update their browsers immediately to ensure these security patches are applied. Additionally, developers should review any custom implementations of copy-paste or drag-and-drop functionality within web applications to ensure they adhere to strict input validation standards and utilize modern browser APIs that enforce secure defaults. Regular auditing of content security policies and monitoring for anomalous clipboard activity can further reduce the risk associated with similar vulnerabilities in future software versions.