CVE-2026-12294 Sandbox escape in the DOM: Workers component
Attackers can escape the browser sandbox via the DOM Workers component, potentially executing arbitrary code.
- 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-2026-12294?
CVE-2026-12294 is a critical vulnerability in Mozilla Firefox, published on 16 Jun 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 in the DOM: Workers component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
Which versions are affected by CVE-2026-12294?
It affects 2 products.
Products include Mozilla Firefox, Mozilla Thunderbird.
How do I fix CVE-2026-12294?
Upgrade to a fixed version.
Is CVE-2026-12294 being exploited?
There is no known exploitation of CVE-2026-12294 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as DEBIAN-CVE-2026-12294, GHSA-j3ch-r4qx-fpvf, UBUNTU-CVE-2026-12294.