CVE-2026-12297: Sandbox escape due to incorrect boundary conditions in the Networking component

Published Jun 16, 2026
·
Updated

Sandbox escape due to incorrect boundary conditions in the Networking component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

Affected Software

10 affected componentsFixes available
Mozilla Firefox ESR<140.12
140.12
Mozilla Firefox<152
152
Mozilla Firefox ESR<115.37
115.37
Mozilla Thunderbird<140.12
140.12
Mozilla Thunderbird<152
152
Mozilla Firefox<115.37.0
Mozilla Firefox<152.0.0
Mozilla Firefox>=128.0<140.12.0
Mozilla Thunderbird<140.12.0
Mozilla Thunderbird<152.0.0

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 140.12
  2. Upgrade

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

    Fixed in 152
  3. Upgrade

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

    Fixed in 115.37
  4. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 152
  5. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 140.12
  6. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 115.37
  7. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 152
  8. Upgrade

    Upgrade Thunderbird ESR to a version that resolves this vulnerability.

    Fixed in 140.12

Event History

Jun 16, 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·11:52 AM
Data Sourced
via MITRE·11:52 AM
Description
Data Sourced
via NVD·01:16 PM
DescriptionSeverityWeaknessAffected Software
Data Sourced
via Red Hat·02:02 PM
DescriptionSeverityAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

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Frequently Asked Questions

1

What is the severity of CVE-2026-12297?

The severity of CVE-2026-12297 is high with a score of 7.

2

What is CVE-2026-12297?

CVE-2026-12297 is a vulnerability that allows sandbox escape due to incorrect boundary conditions in the Networking component.

3

How do I fix CVE-2026-12297?

To fix CVE-2026-12297, update to Firefox version 152, Firefox ESR version 140.12 or 115.37, or Thunderbird version 152 or 140.12.

4

What products are affected by CVE-2026-12297?

CVE-2026-12297 affects Mozilla Firefox, Mozilla Firefox ESR, and Mozilla Thunderbird.

5

When was CVE-2026-12297 published?

CVE-2026-12297 was published on June 16, 2026.

Company

Resources

Contact

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