DOM Spoofing Vulnerability in Firefox Copy-Paste and Drag-Drop

Publication date: 2026-01-13

Last updated on: 2026-04-13

Assigner: Mozilla Corporation

Description

Spoofing issue in the DOM: Copy & Paste and Drag & Drop component. This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

CVSS Scores

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Meta Information

Published

2026-01-13

Last Modified

2026-04-13

Generated

2026-07-06

AI Q&A

2026-01-14

EPSS Evaluated

2026-07-05

NVD

CVE-2026-0890

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 147 (exc)
mozilla	firefox_esr	to 140.7 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-290	This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.

Attack-Flow Graph

Executive Summary

This vulnerability is a spoofing issue in the Document Object Model (DOM) related to the Copy & Paste and Drag & Drop components in Firefox versions before 147 and Firefox ESR before 140.7. It allows attackers to bypass existing security mitigations within the DOM, potentially enabling unauthorized actions or exploitation within the browser environment. [2]

Impact Analysis

The vulnerability can allow attackers to circumvent security measures in the browser's DOM, which may lead to unauthorized actions or exploitation such as spoofing attacks. This could compromise the integrity of user interactions like Copy & Paste and Drag & Drop, potentially leading to misleading or malicious content being executed or displayed. [2]

Mitigation Strategies

To mitigate this vulnerability, update Firefox to version 147 or later, or Firefox ESR to version 140.7 or later, where the issue has been fixed as part of security updates addressing this and other vulnerabilities. [1, 2]

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