CVE-2026-92068 Site isolation issue in the Reader Mode component

Medium 5.4 Published Updated

A site isolation flaw in Reader Mode allows bypassing security boundaries, requiring users to upgrade Firefox or Thunderbird.

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-2026-92068?

CVE-2026-92068 is a medium-severity vulnerability in Mozilla Firefox, published on 15 Sep 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

Site isolation issue in the Reader Mode component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.

Weakness: CWE-346

Which versions are affected by CVE-2026-92068?

It affects 2 products.

Products include Mozilla Firefox, Mozilla Thunderbird.

How do I fix CVE-2026-92068?

Upgrade to a fixed version.

Is CVE-2026-92068 being exploited?

There is no known exploitation of CVE-2026-92068 in the wild and no public exploit code.

All Mozilla Firefox vulnerabilities

Sources

Also known as DEBIAN-CVE-2026-92068, GHSA-jgrj-mv42-4xrq, UBUNTU-CVE-2026-92068.

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