Firefox Sandbox Escape in WebRTC Networking before ESR 140.10.1
CVE-2026-7321 Published on April 28, 2026
Sandbox escape due to incorrect boundary conditions in the WebRTC: Networking component
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.
Vulnerability Analysis
CVE-2026-7321 can be exploited with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.
Weakness Type
What is a Classic Buffer Overflow Vulnerability?
The program 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, leading to a buffer overflow. A buffer overflow condition exists when a program attempts to put more data in a buffer than it can hold, or when a program attempts to put data in a memory area outside of the boundaries of a buffer. The simplest type of error, and the most common cause of buffer overflows, is the "classic" case in which the program copies the buffer without restricting how much is copied. Other variants exist, but the existence of a classic overflow strongly suggests that the programmer is not considering even the most basic of security protections.
CVE-2026-7321 has been classified to as a Classic Buffer Overflow vulnerability or weakness.
Products Associated with CVE-2026-7321
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Affected Versions
Mozilla Firefox:- Version 140.10.1, <= 140.* is unaffected.
- Version 150, <= * is unaffected.
- Version 140.10.1, <= 140.* is unaffected.
- Version 150, <= * is unaffected.