What is CVE-2026-2919?

CVE-2026-2919 is a medium-severity vulnerability in Mozilla Firefox Focus, classified under User Interface (UI) Misrepresentation of Critical Information. CVSS score: 4.3/10. Published 2026-03-09.

How severe is CVE-2026-2919?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Mozilla Firefox Focus

CVE-2026-2919

Malicious scripts could display attacker-controlled web content under spoofed domains in Focus for iOS by stalling a _self navigation to an invalid port and triggering an iframe redirect, causing the UI to display a trusted domain without user interaction. This vulnerability was fixed in Focus for iOS 148.2.

Published 2026-03-09 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (16.2th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 16.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

Mozilla Firefox Focus
Mozilla Focus For iOS — versions 148.2

Weakness classification (CWE)

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

References

bugzilla.mozilla.org/show_bug.cgi (Permissions Required)
www.mozilla.org/security/advisories/mfsa2026-18/ (Vendor Advisory)

Frequently asked questions

What is CVE-2026-2919?: CVE-2026-2919 is a medium-severity vulnerability in Mozilla Firefox Focus, classified under User Interface (UI) Misrepresentation of Critical Information. CVSS score: 4.3/10. Published 2026-03-09.
How severe is CVE-2026-2919?: Medium severity. CVSS v3 base score is 4.3 out of 10.