CVE-2026-100816: Site isolation issue in the DOM: Networking component

Published Sep 29, 2026
·
Updated

Site isolation issue in the DOM: Networking component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.

Affected Software

8 affected componentsFixes available
Mozilla Firefox<157
157
Mozilla Firefox ESR<153.4
153.4
Mozilla Thunderbird<157
157
Mozilla Thunderbird<153.4
153.4
Mozilla Firefox<153.4.0
Mozilla Firefox>=154.0.0<157.0.0
Mozilla Thunderbird<153.4.0
Mozilla Thunderbird>=154.0<157.0

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 157
  2. Upgrade

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

    Fixed in 153.4
  3. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 153.4
  4. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 157
  5. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 153.4
  6. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 157

Event History

Sep 29, 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·12:36 PM
Data Sourced
via MITRE·12:36 PM
Description
Data Sourced
via NVD·01:17 PM
DescriptionSeverityWeaknessAffected Software
Sep 30, 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 products are identified as affected?

The listed products are Mozilla Firefox and Mozilla Firefox ESR.

2

Are affected versions or fixed versions provided?

No affected or fixed version numbers are included in the available data.

Company

Resources

Contact

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