CVE-2026-40688 Memory corruption in FortiWeb

What is CVE-2026-40688?

CVE-2026-40688 is a medium-severity memory corruption vulnerability in Fortinet Fortiweb, published on 14 Apr 2026. An attacker needs administrator access to exploit it, with no action from the victim.

Official description

An out-of-bounds write vulnerability [CWE-787] vulnerability in Fortinet FortiWeb 8.0.0 through 8.0.3, FortiWeb 7.6.0 through 7.6.6, FortiWeb 7.4.0 through 7.4.11 may allow a remote privileged attacker to execute arbitrary code or command via crafted HTTP requests.

Weakness: CWE-787

Which versions are affected by CVE-2026-40688?

It affects 1 product.

Products include Fortinet Fortiweb.

How do I fix CVE-2026-40688?

No fix has been published for CVE-2026-40688 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-40688 being exploited?

There is no known exploitation of CVE-2026-40688 in the wild and no public exploit code.

Other vulnerabilities in Fortinet Fortiweb

• CVE-2025-25257 Fortinet FortiWeb SQL Injection Exploited Critical 9.6
• CVE-2025-64446 Fortinet FortiWeb Path Traversal Exploited Critical 9.4
• CVE-2025-58034 Fortinet FortiWeb OS Command Injection Exploited Medium 6.7
• CVE-2020-29015 SQL injection in Fortinet FortiWeb Critical 9.8
• CVE-2020-29016 Memory corruption in Fortinet FortiWeb Critical 9.8

All Fortinet Fortiweb vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-m3qh-6w2c-jgrx.