CVE-2026-45150

Zen Browser - Missing Fullscreen Security Notification Allows Origin Spoofing

State: Published
Severity: 6.3 Medium
Published: Jul 15, 2026
Updated: Jul 15, 2026
Reserved: May 8, 2026

Description

Zen is a firefox-based browser. Prior to 1.19.13b, Zen Browser did not provide a persistent, clearly visible security notification when a webpage entered fullscreen mode, allowing an attacker-controlled page to hide the real browser UI and origin information, imitate a trusted website UI, and combine with long-domain URL eliding to spoof a trusted origin for phishing and credential theft. This issue is fixed in version 1.19.13b.

Scores

CVSS	Score	Vector	Source
4.0	6.3 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N	GitHub_M

Weaknesses

CWE-451 User Interface (UI) Misrepresentation of Critical Information

Affected Products

Product	Versions
desktopzen-browser	< 1.19.13bAffected

References

https://github.com/zen-browser/desktop/security/advisories/GHSA-vjfv-85qf-v25c

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