CVE-2026-74984: Race condition in the JavaScript Engine component

Q: Which Firefox releases include the fix?

The issue is fixed in Firefox 154 and Firefox ESR 153.1. Check the installed browser version and update to the applicable fixed release or later.

Published Aug 18, 2026

Updated

Race condition in the JavaScript Engine component. This vulnerability was fixed in Firefox 154 and Firefox ESR 153.1.

Affected Software

4 affected componentsFixes available

Mozilla Firefox<154

Firefox ESR<153.1

Mozilla Firefox<154

154

Mozilla Firefox ESR<153.1

153.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 154
Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 153.1
Upgrade
Upgrade Firefox JavaScript Engine to a version that resolves this vulnerability.
Fixed in 154
Upgrade
Upgrade Firefox ESR JavaScript Engine to a version that resolves this vulnerability.
Fixed in 153.1

Event History

Aug 18, 2026

CVE Published

via Mozilla·12:00 AM

Data Sourced

via Mozilla·12:00 AM

DescriptionSeverityAffected Software

Updated

via Mozilla·12:00 AM

Affected Software

CVE Published

via MITRE·12:23 PM

Data Sourced

via MITRE·12:23 PM

Description

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

Which Firefox releases include the fix?

The issue is fixed in Firefox 154 and Firefox ESR 153.1. Check the installed browser version and update to the applicable fixed release or later.

CVE-2026-74984: Race condition in the JavaScript Engine component

Affected Software

Remediation

Event History

Parent advisories

Peer vulnerabilities

Frequently Asked Questions

Which Firefox releases include the fix?

Company

Resources

Contact