Vulnerability · Published Jul 15, 2026 · Assigned by GitHub_M

CVE-2026-45150Zen Browser - Missing Fullscreen Security Notification Allows Origin Spoofing

Medium 6.3

In plain English

A medium-severity security flaw in desktop from zen-browser. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities).

Severity (CVSS 4.0)6.3Medium

Exploit odds (30 days)0.3%top 75.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
zen-browser	desktop	< 1.19.13b

Weakness: CWE-451 · Vector: 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

References

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