Spoofing attack in Firefox for iOS - CVE-2026-13356
Published: July 22, 2026
Vulnerability identifier: #VU139186
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-2026-13356
CWE-ID: CWE-451
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Mozilla
Affected software:
Firefox for iOS
Firefox for iOS
Detailed vulnerability description
The vulnerability allows a remote attacker to spoof the address bar origin.
The vulnerability exists due to improper user interface handling in the browser UI when processing interrupted navigation. A remote attacker can enqueue a synchronous javascript dialog from a malicious webpage to spoof the address bar origin.
The issue occurs when a pending navigation is interrupted, causing the browser to display the destination origin while continuing to render attacker-controlled content.
How to mitigate CVE-2026-13356
Install security update from vendor's website.