REDHAT-BUG-2503491: Use After Free

Published Jul 21, 2026

Updated

Sandbox escape due to use-after-free in the DOM: Navigation component. This vulnerability was fixed in Firefox 153, Firefox ESR 115.38, and Firefox ESR 140.13.

Affected Software

2 affected components

Mozilla Firefox=153

Mozilla Firefox ESR=115.38, =140.13

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade Firefox to a version that resolves this vulnerability.
Fixed in 153
Upgrade
Upgrade Firefox ESR to a version that resolves this vulnerability.
Fixed in 115.38
Upgrade
Upgrade Firefox ESR to a version that resolves this vulnerability.
Fixed in 140.13

Event History

Jul 21, 2026

Data Sourced

via Red Hat·01:04 PM

DescriptionSeverityAffected Software

Frequently Asked Questions

What is the severity of REDHAT-BUG-2503491?

The severity of REDHAT-BUG-2503491 is classified as high with a score of 7.

How do I fix REDHAT-BUG-2503491?

To fix REDHAT-BUG-2503491, update to Firefox version 153, Firefox ESR 115.38, or Firefox ESR 140.13.

What does REDHAT-BUG-2503491 entail?

REDHAT-BUG-2503491 involves a sandbox escape vulnerability due to use-after-free in the DOM Navigation component.

Which software is affected by REDHAT-BUG-2503491?

REDHAT-BUG-2503491 affects Mozilla Firefox and Mozilla Firefox ESR.

When was REDHAT-BUG-2503491 published?

REDHAT-BUG-2503491 was published on July 21, 2026.