Input validation error in Mozilla Firefox and Firefox for Android - CVE-2026-16378
Published: July 22, 2026
Vulnerability identifier: #VU139002
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-16378
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Mozilla
Affected software:
Mozilla Firefox
Firefox for Android
Mozilla Firefox
Firefox for Android
Detailed vulnerability description
The vulnerability allows a remote attacker to perform unauthorized actions.
The vulnerability exists due to improper input handling in the DOM: Copy & Paste and Drag & Drop component when handling copy, paste, and drag-and-drop operations. A remote attacker can trigger crafted user interface interactions to perform unauthorized actions.
How to mitigate CVE-2026-16378
Install security update from vendor's website.