What is CVE-2026-16397?

CVE-2026-16397 is a medium-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Rendered UI Layers or Frames (Clickjacking). CVSS score: 6.5/10. Published 2026-07-21.

How severe is CVE-2026-16397?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Mozilla Firefox

CVE-2026-16397

Clickjacking issue in the WebExtensions component in Firefox for Android. This vulnerability was fixed in Firefox 153.

EPSS: 0.002 (7.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.

Affected products

Mozilla Firefox — versions 153

Weakness classification (CWE)

CWE-1021 — Improper Restriction of Rendered UI Layers or Frames (Clickjacking)

References

security@mozilla.org (Permissions Required)
security@mozilla.org (Vendor Advisory)

Frequently asked questions

What is CVE-2026-16397?: CVE-2026-16397 is a medium-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Rendered UI Layers or Frames (Clickjacking). CVSS score: 6.5/10. Published 2026-07-21.
How severe is CVE-2026-16397?: Medium severity. CVSS v3 base score is 6.5 out of 10.