CVE-2026-109705: Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the Networking component

Published Oct 13, 2026
·
Updated

Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the Networking component. This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5.

Affected Software

2 affected componentsFixes available
Mozilla Firefox<158
158
Mozilla Firefox ESR<153.5
153.5

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 158
  2. Upgrade

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

    Fixed in 153.5
  3. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 158
  4. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 153.5

Event History

Oct 13, 2026
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
CVE Published
via MITRE·12:29 PM
Data Sourced
via MITRE·12:29 PM
Description
Data Sourced
via NVD·01:17 PM
DescriptionSeverityWeakness

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

Which Firefox releases include the fix?

The vulnerability was fixed in Firefox 158 and Firefox ESR 153.5.

2

Does exploitation require authentication or prior local access?

The CVSS vector indicates network attackability with low attack complexity and no privileges required. It also indicates user interaction is required.

3

What security impact could successful exploitation have?

The CVSS vector rates impacts to confidentiality, integrity, and availability as high, with scope changed. The issue involves a sandbox escape and site-isolation weakness in the Networking component.

Company

Resources

Contact

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