CVE-2026-74979

CRITICAL 9.8

Mitigation bypass in the Add-ons Manager component

CVSS Score

9.8

EPSS Score

0.0%

EPSS Percentile

0th

Mitigation bypass in the Add-ons Manager component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.

Vendor	mozilla
Product	firefox
Ecosystems	Browser JavaScript
Industries	Technology
Published	Aug 18, 2026
Last Updated	Aug 18, 2026

Stay Ahead of the Next One

Get instant alerts for mozilla firefox

Be the first to know when new critical vulnerabilities affecting mozilla firefox are published — delivered to Slack, Telegram or Discord.

Get Free Alerts → Free · No credit card · 60 sec setup

Affected Versions

Mozilla / Firefox

All versions affected

Mozilla / Thunderbird

All versions affected

References

NVD ↗ CVE.org ↗ EPSS Data ↗

bugzilla.mozilla.org: https://bugzilla.mozilla.org/show_bug.cgi?id=2045676 mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-74/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-77/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-78/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-80/

Credits

Tomoya Nakanishi