CVE-2026-74971 Information disclosure in the DOM: UI Events & Focus Handling component

Medium 4.3 Published 18 Aug 2026 Updated 18 Aug 2026

An attacker can exploit a flaw in Firefox's DOM UI Events to disclose sensitive information, requiring users to upgrade to patched versions.

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-2026-74971?

CVE-2026-74971 is a medium-severity vulnerability in Mozilla Firefox, published on 18 Aug 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

Information disclosure in the DOM: UI Events & Focus Handling component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

Weakness: CWE-200

Which versions are affected by CVE-2026-74971?

It affects 2 products.

Products include Mozilla Firefox, Mozilla Thunderbird.

How do I fix CVE-2026-74971?

Upgrade to a fixed version.

Is CVE-2026-74971 being exploited?

There is no known exploitation of CVE-2026-74971 in the wild and no public exploit code.

All Mozilla Firefox vulnerabilities

Sources

Also known as DEBIAN-CVE-2026-74971, GHSA-67f4-mqxj-f332, UBUNTU-CVE-2026-74971.