Is CVE-2026-40688 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-40688 being exploited in the wild.

How severe is CVE-2026-40688?

High severity, with a CVSS score of 7.2, published 14 April 2026.

Which products and versions are affected?

Fortinet FortiWeb 8.0.0 through 8.0.3, 7.6.0 through 7.6.6, 7.4.0 through 7.4.11.

Is there a fix for CVE-2026-40688?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-40688 attacked?

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

Am I affected by CVE-2026-40688?

Check whether you run Fortinet FortiWeb 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-2026-40688: Fortinet FortiWeb out-of-bounds write in CGI daemon

CVE-2026-40688 · Severity: high · CVSS 7.2 · Published 2026-04-14

FortiWeb is a web application firewall designed to protect business applications from cyberattacks. A security flaw in its management interface could allow an administrator with high-level privileges to execute unauthorized commands on the system. While this requires existing administrative access, it could be used by a malicious insider or a compromised admin account to take full control of the security appliance.

Technologies: Fortinet FortiWeb. Vendors: Fortinet.

Quick answers

Is CVE-2026-40688 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-40688 being exploited in the wild.
How severe is CVE-2026-40688?: High severity, with a CVSS score of 7.2, published 14 April 2026.
Which products and versions are affected?: Fortinet FortiWeb 8.0.0 through 8.0.3, 7.6.0 through 7.6.6, 7.4.0 through 7.4.11.
Is there a fix for CVE-2026-40688?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-40688 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-40688?: Check whether you run Fortinet FortiWeb 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.

Technical details

An out-of-bounds write vulnerability (CWE-787) exists in the FortiWeb CGI daemon within the administrative GUI component. The flaw is triggered by processing specially crafted HTTP requests sent to the management interface. An attacker must have high-level administrative privileges (PR:H) to exploit this vulnerability. Successful exploitation allows for arbitrary code execution or command injection with the privileges of the affected daemon. Fortinet has released patches in versions 8.0.4, 7.6.7, and 7.4.12 to address this issue.

Affected products

Fortinet FortiWeb 8.0.0 through 8.0.3, 7.6.0 through 7.6.6, 7.4.0 through 7.4.11

Timeline

2026-04-14: disclosed
2026-04-15: advisory: Initial publication of FG-IR-26-127

References

https://fortiguard.fortinet.com/psirt/FG-IR-26-127

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