CVE-2026-92059 Incorrect boundary conditions in the DOM: Editor component

What is CVE-2026-92059?

CVE-2026-92059 is a critical memory corruption vulnerability in Mozilla Firefox, published on 15 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

Incorrect boundary conditions in the DOM: Editor component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.

Weakness: CWE-119

Which versions are affected by CVE-2026-92059?

It affects 2 products.

Products include Mozilla Firefox, Mozilla Thunderbird.

How do I fix CVE-2026-92059?

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-2026-92059 being exploited?

There is no known exploitation of CVE-2026-92059 in the wild and no public exploit code.

Other vulnerabilities in Mozilla Firefox

• CVE-2019-11708 Mozilla Firefox and Thunderbird Sandbox Escape Exploited Critical 10.0
• CVE-2010-3765 Mozilla Multiple Products Remote Code Execution Exploited Critical 9.8
• CVE-2022-26486 Mozilla Firefox Use-After-Free Exploited Critical 9.6
• CVE-2022-26485 Mozilla Firefox Use-After-Free Exploited High 8.8
• CVE-2019-11707 Mozilla Firefox and Thunderbird Type Confusion Exploited High 8.8

All Mozilla Firefox vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-92059, GHSA-3753-fcfq-39h2, UBUNTU-CVE-2026-92059.