CVE-2026-7321
Received Received - Intake
Sandbox Escape in Firefox WebRTC Networking Component

Publication date: 2026-04-28

Last updated on: 2026-05-01

Assigner: Mozilla Corporation

Description
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.
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Meta Information
Published
2026-04-28
Last Modified
2026-05-01
Generated
2026-06-16
AI Q&A
2026-04-28
EPSS Evaluated
2026-06-15
NVD
CVE-2026-7321
EUVD
EUVD-2026-26058
Affected Vendors & Products
Showing 4 associated CPEs
Vendor Product Version / Range
mozilla firefox to 150.0 (exc)
mozilla thunderbird to 150.0 (exc)
mozilla firefox to 140.10.1 (exc)
mozilla thunderbird to 140.10.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-120 The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
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Executive Summary

CVE-2026-7321 is a security vulnerability in the WebRTC Networking component of Firefox ESR that allows a sandbox escape due to incorrect boundary conditions.

A sandbox escape means that an attacker can break out of the restricted environment (sandbox) that is designed to isolate processes and limit the impact of exploits.

This flaw was fixed in Firefox ESR version 140.10.1 by correcting the boundary condition errors to prevent unauthorized access beyond the sandbox restrictions.

Impact Analysis

This vulnerability can have a severe impact because it allows an attacker to escape the sandbox environment, potentially gaining unauthorized access to system resources.

The CVSS score of 9.6 indicates a critical severity with high impact on confidentiality, integrity, and availability.

An attacker exploiting this flaw could execute arbitrary code or access sensitive information beyond the intended sandbox restrictions.

Mitigation Strategies

To mitigate this vulnerability, you should update Firefox ESR to version 140.10.1 or later, where the issue has been fixed.

This update corrects the incorrect boundary conditions in the WebRTC Networking component that allowed sandbox escape.

Compliance Impact

The provided information does not specify how this vulnerability impacts compliance with common standards and regulations such as GDPR or HIPAA.

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