CVE-2026-74959: Mitigation bypass in the Storage: Cache API component

Published Aug 18, 2026
·
Updated

Mitigation bypass in the Storage: Cache API component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1.

Affected Software

6 affected componentsFixes available
Mozilla Firefox=154
Mozilla Firefox ESR 140.14=140.14
Mozilla Firefox ESR 153.1=153.1
Mozilla Firefox ESR<140.14
140.14
Mozilla Firefox<154
154
Mozilla Firefox ESR<153.1
153.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 140.14
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 154
  3. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 153.1
  4. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 154
  5. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 140.14
  6. Upgrade

    Upgrade Firefox ESR 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.

Frequently Asked Questions

1

Which Firefox versions should be updated?

Firefox installations older than Firefox 154, Firefox ESR 140.14, or Firefox ESR 153.1 have not received the stated fix. The supplied information does not identify any affected configuration, user interaction requirement, or exploitation prerequisites.

2

What should organizations do if they are affected?

Update to Firefox 154, Firefox ESR 140.14, or Firefox ESR 153.1, as applicable. No alternative mitigation or workaround is provided in the available data.

Contact

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