# CVE-2026-126154: Fortinet FortiMail out-of-bounds write in API

Source: https://junglewise.ai/threats/cve-2026-126154-a-out-of-bounds-write-vulnerability-in-fortinet-fortimail-8-0-0  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-11. Updated: 2026-11-11  
License: CC BY 4.0 with a link back

CVE-2026-126154 · Severity: high · CVSS 7.5 · Published 2026-11-11

FortiMail is an email security appliance that filters and protects incoming mail. A remote attacker can crash the mail server by sending a specially crafted HTTP request, causing email delivery to stop. No authentication is required to exploit this vulnerability.

Technologies: [Fortinet FortiMail](https://junglewise.ai/threats/technologies/fortimail). Vendors: [Fortinet](https://junglewise.ai/threats/vendors/fortinet).

## Quick answers

**Is CVE-2026-126154 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-126154 being exploited in the wild.

**How severe is CVE-2026-126154?** 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-2026-126154?** Yes: fixed in FortiMail 7.4.9 and above, 7.6.7 and above, 8.0.2 and above; 7.2 all versions 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-2026-126154 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-126154?** 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 7.4.9 and above, 7.6.7 and above, 8.0.2 and above; 7.2 all versions require migration to a fixed release

## Technical details

An out-of-bounds write vulnerability (CWE-787) in the FortiMail API component allows unauthenticated remote attackers to trigger a denial of service via a specially crafted HTTP request. The vulnerability affects multiple version branches across 7.2, 7.4, 7.6, and 8.0 releases. No exploitation in the wild has been reported.

## 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 patched via firmware updates to 7.6.7 GA or 8.0.2 GA

## References

- [https://fortiguard.fortinet.com/psirt/FG-IR-26-206](https://fortiguard.fortinet.com/psirt/FG-IR-26-206)

## Related threats

- [Fortinet FortiMail SQL injection](https://junglewise.ai/threats/cve-2026-126263-a-improper-neutralization-of-special-elements-used-in-an-sql)
- [Fortinet FortiMail argument injection in administrative interface](https://junglewise.ai/threats/cve-2026-126169-a-improper-neutralization-of-argument-delimiters-in-a-command)
- [Fortinet FortiMail argument injection in administrative interface](https://junglewise.ai/threats/cve-2026-126168-a-improper-neutralization-of-argument-delimiters-in-a-command)
- [Fortinet FortiMail command injection in admin GUI](https://junglewise.ai/threats/cve-2026-126167-a-improper-neutralization-of-special-elements-used-in-a-command)
- [Fortinet FortiMail argument injection in admin interface](https://junglewise.ai/threats/cve-2026-126166-a-improper-neutralization-of-argument-delimiters-in-a-command)