CVE-2026-7321 Sandbox escape due to incorrect boundary conditions in the WebRTC: Networking component
A sandbox escape in WebRTC networking allows attackers to execute arbitrary code or escalate privileges, affecting Firefox and Thunderbird users.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-7321?
CVE-2026-7321 is a critical memory corruption vulnerability in Mozilla Firefox, published on 28 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-120
Which versions are affected by CVE-2026-7321?
It affects 2 products.
Products include Mozilla Firefox, Mozilla Thunderbird.
How do I fix CVE-2026-7321?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-7321 being exploited?
There is no known exploitation of CVE-2026-7321 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as CLSA-2026-1781619768, DEBIAN-CVE-2026-7321, GHSA-jjvw-q2ff-g9g3.