CVE-2026-44659 MEDIUM

CVE-2026-44659: Zen Browser Mac - Address Bar Spoofing via Long Subdomain

Vendor Zen-Browser
Product desktop
Weakness CWE-451
Published May 11, 2026
Last update May 12, 2026

CVSS base score

4.7/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction Required
Confidentiality None
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N

What the vulnerability does

01Description

Zen is a firefox-based browser. Prior to 1.19.12b, the ZEN Browser incorrectly truncates long hostnames in the address bar and shows only the attacker-controlled prefix of the subdomain, hiding the actual registrable domain (eTLD+1). As a result, an attacker can craft extremely long malicious subdomains that visually imitate trusted brands, and the browser will display only the spoofed prefix, misleading users about the actual origin of the site. This directly compromises the URL bar as a security indicator and creates a phishing/supply-chain attack vector. This vulnerability is fixed in 1.19.12b.

Key dates

02Disclosure timeline

May 11, 2026 CVE published
May 12, 2026 Record updated