Is CVE-2026-126165 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-126165 being exploited in the wild.

How severe is CVE-2026-126165?

High severity, with a CVSS score of 7.5, published 11 November 2026.

Which products and versions are affected?

Fortinet FortiMail 7.2 all versions, 7.4.0–7.4.8, 7.6.0–7.6.6, 8.0.0–8.0.1.

Is there a fix for CVE-2026-126165?

Yes: fixed in FortiMail 8.0.2, 7.6.7, 7.4.9; FortiMail 7.2 and 7.0 require migration to a fixed release. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-126165 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-126165?

Check whether you run Fortinet FortiMail at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-126165: Fortinet FortiMail memory allocation DoS

CVE-2026-126165 · Severity: high · CVSS 7.5 · Published 2026-11-11

FortiMail is an email security gateway that scans incoming messages for threats. A flaw in how it processes email attachments can cause it to allocate excessive memory when handling specially crafted messages, leading to denial of service. An attacker can crash the email service by sending a malicious attachment via SMTP, preventing legitimate email delivery.

Technologies: Fortinet FortiMail. Vendors: Fortinet.

Quick answers

Is CVE-2026-126165 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-126165 being exploited in the wild.
How severe is CVE-2026-126165?: High severity, with a CVSS score of 7.5, published 11 November 2026.
Which products and versions are affected?: Fortinet FortiMail 7.2 all versions, 7.4.0–7.4.8, 7.6.0–7.6.6, 8.0.0–8.0.1.
Is there a fix for CVE-2026-126165?: Yes: fixed in FortiMail 8.0.2, 7.6.7, 7.4.9; FortiMail 7.2 and 7.0 require migration to a fixed release. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-126165 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-126165?: Check whether you run Fortinet FortiMail at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: FortiMail 8.0.2, 7.6.7, 7.4.9; FortiMail 7.2 and 7.0 require migration to a fixed release

Technical details

A memory allocation with excessive size value vulnerability (CWE-789) in the FortiMail API component allows unauthenticated remote attackers to trigger unbounded memory allocation via a specially crafted SMTP attachment. The flaw requires no authentication or user interaction and results in service denial through resource exhaustion. Patches are available for all affected versions.

Affected products

Fortinet FortiMail 7.2 all versions, 7.4.0–7.4.8, 7.6.0–7.6.6, 8.0.0–8.0.1

Timeline

2026-11-10: disclosed
2026-10-05: patched: FortiMail Cloud remediated

References

https://fortiguard.fortinet.com/psirt/FG-IR-26-217

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