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CVE-2026-16397 Mozilla CVE debrief

A clickjacking issue was found in the WebExtensions component of Firefox for Android. This issue has been fixed in Firefox 153. The vulnerability has a CVSS score of 6.5 and a severity of MEDIUM. Users of Firefox for Android, particularly those who use WebExtensions, should apply the update to Firefox 153 to mitigate this vulnerability. To address this vulnerability, users should review and restrict WebExtensions usage and monitor for suspicious activity. Operators should review compensating controls for exposed systems while remediation is scheduled and verified. Evidence limits suggest verifying WebExtensions usage and Firefox version, and reviewing the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Vendor
Mozilla
Product
Firefox
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-21
Original CVE updated
2026-07-22
Advisory published
2026-07-21
Advisory updated
2026-07-22

Who should care

Users of Firefox for Android, particularly those who use WebExtensions, should apply the update to Firefox 153 to mitigate this vulnerability. Operators should review compensating controls for exposed systems while remediation is scheduled and verified.

Technical summary

The CVE-2026-16397 vulnerability is a clickjacking issue in the WebExtensions component of Firefox for Android. The vulnerability has a CVSS score of 6.5 and a severity of MEDIUM. It was published on 2026-07-21T13:17:14.977Z and last modified on 2026-07-22T18:29:21.307Z. The vulnerability was fixed in Firefox 153. Users should review and restrict WebExtensions usage and monitor for suspicious activity.

Defensive priority

Medium priority for users of Firefox for Android with WebExtensions.

Recommended defensive actions

  • Update Firefox to version 153 or later
  • Review and restrict WebExtensions usage
  • Monitor for suspicious activity
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
  • Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
  • Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review.

Evidence notes

The CVE record was published on 2026-07-21T13:17:14.977Z and last modified on 2026-07-22T18:29:21.307Z. The NVD entry is currently Analyzed. The vulnerability affects Firefox for Android users with WebExtensions. Evidence limits suggest verifying WebExtensions usage and Firefox version.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-21T13:17:14.977Z and has not been modified since then. The NVD entry is currently Analyzed.