CVE-2026-7321: Sandbox escape due to incorrect boundary conditions in the WebRTC: Networking component

Published Apr 21, 2026
·
Updated

Sandbox escape due to incorrect boundary conditions in the WebRTC: Networking component. This vulnerability was fixed in Firefox 150, Thunderbird 150, Firefox ESR 140.10.1, and Thunderbird 140.10.1.

Other sources

Sandbox escape due to incorrect boundary conditions in the WebRTC: Networking component. This vulnerability was fixed in Firefox ESR 140.10.1.

— Red Hat

Affected Software

9 affected componentsFixes available
Mozilla Firefox ESR<140.10.1
Mozilla Firefox ESR<140.10.1
140.10.1
Mozilla Firefox<150
150
Mozilla Thunderbird<150
150
Mozilla Thunderbird<140.10.1
140.10.1
Mozilla Firefox<140.10.1
Mozilla Firefox<150.0
Mozilla Thunderbird<140.10.1
Mozilla Thunderbird<150.0

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 140.10.1
  2. Upgrade

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

    Fixed in 150
  3. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 150
  4. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 150
  5. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 140.10.1
  6. Upgrade

    Upgrade Thunderbird ESR to a version that resolves this vulnerability.

    Fixed in 140.10.1

Event History

Apr 21, 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
Apr 28, 2026
Updated
via Mozilla·12:00 AM
Affected Software
CVE Published
via MITRE·01:49 PM
Data Sourced
via MITRE·01:49 PM
Description
Data Sourced
via Red Hat·03:01 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·03:16 PM
DescriptionSeverityWeaknessAffected Software
Apr 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.

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Frequently Asked Questions

1

What is the severity of CVE-2026-7321?

CVE-2026-7321 has been classified with a high severity rating due to the potential for sandbox escape.

2

How do I fix CVE-2026-7321?

To mitigate CVE-2026-7321, update to Firefox or Thunderbird version 150 or Firefox ESR version 140.10.1 or later.

3

What components are affected by CVE-2026-7321?

CVE-2026-7321 affects the WebRTC: Networking component in Mozilla products.

4

Is CVE-2026-7321 applicable to older versions of Mozilla Firefox?

Yes, CVE-2026-7321 is applicable to versions prior to Firefox and Thunderbird 150 and Firefox ESR 140.10.1.

5

What could be the impact of exploiting CVE-2026-7321?

Exploiting CVE-2026-7321 could allow attackers to escape the sandbox, potentially gaining unauthorized access to system resources.

Company

Resources

Contact

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