CVE-2026-92065: Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component

Published Sep 15, 2026
·
Updated

Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.

Affected Software

10 affected componentsFixes available
Mozilla Firefox
Mozilla Firefox ESR
Mozilla Firefox<156
156
Mozilla Firefox ESR<153.3
153.3
Mozilla Thunderbird<156
156
Mozilla Thunderbird<153.3
153.3
Mozilla Firefox<153.3.0
Mozilla Firefox>=154.0.0<156.0.0
Mozilla Thunderbird<153.3.0
Mozilla Thunderbird>=154.0<156.0

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 156
  2. Upgrade

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

    Fixed in 153.3
  3. Upgrade

    Upgrade Firefox (Win32) / Thunderbird (Win32) to a version that resolves this vulnerability.

    Fixed in 156
  4. Upgrade

    Upgrade Firefox ESR (Win32) / Thunderbird ESR (Win32) to a version that resolves this vulnerability.

    Fixed in 153.3

Event History

Sep 15, 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·12:34 PM
Data Sourced
via MITRE·12:34 PM
Description
Data Sourced
via NVD·01:17 PM
DescriptionSeverityWeaknessAffected Software
Sep 16, 2026
Updated
via Mozilla·12:00 AM
Affected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

Which Firefox releases contain the fix?

The issue was fixed in Firefox 156 and Firefox ESR 153.3.

2

What component is involved in this issue?

The vulnerability affects the Widget: Win32 component.

Company

Resources

Contact

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