# CVE-2026-40688: Memory corruption in FortiWeb

> A remote privileged attacker can execute arbitrary code via crafted HTTP requests due to an out-of-bounds write in FortiWeb.

- **Severity:** Medium 6.7 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Apr 2026
- **Updated:** 16 Apr 2026
- **Also known as:** GHSA-m3qh-6w2c-jgrx

## 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 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-40688?

It affects 1 product.


Products: 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.

## 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](https://insights.sbomify.com/CVE-2025-25257/): Fortinet FortiWeb SQL Injection (critical 9.6, exploited in the wild)
- [CVE-2025-64446](https://insights.sbomify.com/CVE-2025-64446/): Fortinet FortiWeb Path Traversal (critical 9.4, exploited in the wild)
- [CVE-2025-58034](https://insights.sbomify.com/CVE-2025-58034/): Fortinet FortiWeb OS Command Injection (medium 6.7, exploited in the wild)
- [CVE-2020-29015](https://insights.sbomify.com/CVE-2020-29015/): SQL injection in Fortinet FortiWeb (critical 9.8)
- [CVE-2020-29016](https://insights.sbomify.com/CVE-2020-29016/): Memory corruption in Fortinet FortiWeb (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40688 and fix it if it is affected.

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

Affected product: Fortinet Fortiweb. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-40688/ (Markdown: https://insights.sbomify.com/CVE-2026-40688/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40688
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40688
- OSV: https://osv.dev/vulnerability/CVE-2026-40688

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40688/
Summaries are generated and may contain mistakes; the official description above is the record.