CVE-2026-126151 Auth bypass in FortiMail

High 7.5 Published Updated

Unauthenticated remote attackers can take over FortiMail accounts via a crafted request exploiting flawed authentication.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Over the internet
Victim action needed
Not needed
Harmful if only installed
No
Needs a specific call
No
Fix
None listed

What is CVE-2026-126151?

CVE-2026-126151 is a high-severity authentication bypass vulnerability in Fortinet FortiMail, published on 11 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A incorrect implementation of authentication algorithm vulnerability in Fortinet FortiMail 8.0.0 through 8.0.1, FortiMail 7.6.0 through 7.6.6, FortiMail 7.4.0 through 7.4.8, FortiMail 7.2 all versions may allow an unauthenticated remote attacker to gain elevation of privilege (account takeover) via a crafted request.

Weakness: CWE-303

Which versions are affected by CVE-2026-126151?

An affected version is exposed as installed. No special setting or call is needed.

How do I fix CVE-2026-126151?

No fix has been published for CVE-2026-126151 yet. Limit exposure of the affected software until one is available.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2026-126151 being exploited?

There is no known exploitation of CVE-2026-126151 in the wild and no public exploit code.

Sources

Also known as GHSA-p457-9wpj-6qgw.

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