CVE-2026-16409 Invalid pointer in the Security: PSM component

High 7.5 Published Updated

An invalid pointer in the PSM component can cause a crash, requiring users to upgrade Firefox and Thunderbird.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Over the internet
Victim action needed
Not needed
Fix
Available

What is CVE-2026-16409?

CVE-2026-16409 is a high-severity vulnerability in Mozilla Firefox, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Invalid pointer in the Security: PSM component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

Weakness: CWE-824

Which versions are affected by CVE-2026-16409?

It affects 2 products.

Products include Mozilla Firefox, Mozilla Thunderbird.

How do I fix CVE-2026-16409?

Upgrade to a fixed version.

Is CVE-2026-16409 being exploited?

There is no known exploitation of CVE-2026-16409 in the wild and no public exploit code.

All Mozilla Firefox vulnerabilities

Sources

Also known as GHSA-gcmc-83gc-jhq6, UBUNTU-CVE-2026-16409.

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