REDHAT-BUG-2517858: Medium severity Mozilla Firefox vulnerability

Q: Which Firefox releases contain the fix?

The issue was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1.

Q: Which products should be checked for exposure?

Mozilla Firefox and Mozilla Firefox ESR should be checked. Versions earlier than the listed fixed releases may be affected.

Published Aug 18, 2026

Updated

Same-origin policy bypass in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1.

Affected Software

2 affected components

Mozilla Firefox<154

Mozilla Firefox ESR<140.14, <153.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade Firefox to a version that resolves this vulnerability.
Fixed in 154
Upgrade
Upgrade Firefox ESR to a version that resolves this vulnerability.
Fixed in 140.14
Upgrade
Upgrade Firefox ESR to a version that resolves this vulnerability.
Fixed in 153.1

Event History

Aug 18, 2026

Data Sourced

via Red Hat·12:56 PM

DescriptionSeverityAffected Software

Frequently Asked Questions

Which Firefox releases contain the fix?

The issue was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1.

Which products should be checked for exposure?

Mozilla Firefox and Mozilla Firefox ESR should be checked. Versions earlier than the listed fixed releases may be affected.