🔐 CVE Alert

CVE-2026-4723

CRITICAL 9.8

Use-after-free in the JavaScript Engine component

CVSS Score
9.8
EPSS Score
0.0%
EPSS Percentile
0th

Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149 and Thunderbird 149.

Vendor mozilla
Product firefox
Ecosystems
Industries
Technology
Published Mar 24, 2026
Last Updated Apr 13, 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=2013573 mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-20/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-23/

Credits

Evyatar Ben Asher, Keane Lucas, Nicholas Carlini, Newton Cheng, Daniel Freeman, Alex Gaynor, and Joel Weinberger using Claude from Anthropic