ZDI-26-265: Fortinet FortiWeb cgi_buf_alloc Integer Overflow Denial-of-Service Vulnerability

Published Apr 15, 2026
·
Updated

This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of Fortinet FortiWeb. Authentication is required to exploit this vulnerability. The ZDI has assigned a CVSS rating of 6.5. The following CVEs are assigned: CVE-2026-39811.

Affected Software

1 affected component
Fortinet FortiWeb

Event History

Apr 15, 2026
Advisory Published
via ZDI·05:00 AM
Data Sourced
via ZDI·05:00 AM
Description
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Frequently Asked Questions

1

What is the severity of ZDI-26-265?

ZDI-26-265 is categorized as a denial-of-service vulnerability, with the potential to significantly disrupt Fortinet FortiWeb services.

2

How do I fix ZDI-26-265?

To mitigate ZDI-26-265, ensure your Fortinet FortiWeb is updated to the latest security patches provided by Fortinet.

3

Who can exploit ZDI-26-265?

ZDI-26-265 can be exploited by remote attackers, although authentication is required to initiate the attack.

4

What impact does ZDI-26-265 have on Fortinet FortiWeb?

Exploiting ZDI-26-265 could lead to an integer overflow, resulting in a denial-of-service condition on affected systems.

5

Is authentication required for ZDI-26-265 exploitation?

Yes, authentication is required to exploit the ZDI-26-265 vulnerability on Fortinet FortiWeb.

Contact

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