TI-2026-32559 Aliases CVE-2026-44659

Zen Browser Mac - Address Bar Spoofing via Long Subdomain

LOW 21CWE-451Published 2026-05-11 · Updated 2026-05-12

Key facts

Attack vector: Network
Privileges required: None
User interaction: Required
Attack complexity: Low
Impact type: Spoofing
Confidentiality · integrity · availability: None · Low · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-451.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00164 5th percentileScored 2026-11-07

Fix Fixed desktop (zen-browser): 1.19.12b

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
zen-browser	desktop	before 1.19.12b	1.19.12b	Patch available	CNA

desktop Vendorzen-browser Affected before 1.19.12b Fixed in 1.19.12b Patch available CNA

Remediation

Fix · CNA desktop (zen-browser) Fixed in 1.19.12b

Timeline

2026-10-02 Threatist record created from CVE-2026-44659

References

Other 1

https://github.com/zen-browser/desktop/security/advisories/GHSA-7p2r-fp29-9w69

TI-2026-30030 Zen Browser MAR updater ships with signature verification removed — unsigned updates accepted CVSS 3.1HIGH 8.0
TI-2026-32978 Zen Browser - Missing Fullscreen Security Notification Allows Origin Spoofing CVSS 4.0MEDIUM 6.3
TI-2026-32558 Zen Browser: RSS Live-Folder Item URLs Are Not Scheme-Restricted Before Trusted Tab Creation CVSS 3.1LOW 2.4
TI-2026-41404 Zen: Context-menu "Open link in glance" / "Split link in new tab" loads a page-controlled… CVSS 3.1N/A 0.0

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences