# CVE-2023-40718: Security feature bypass in IPS Engine

> Attackers can evade Intrusion Prevention System features by sending crafted TCP packets due to an interpretation conflict in the Fortinet IPS Engine.

- **Severity:** Medium 6.7 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:F/RL:O/RC:R`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Oct 2023
- **Updated:** 18 Sep 2024
- **Also known as:** GHSA-hgv6-x3p4-q38v

## What is CVE-2023-40718?

CVE-2023-40718 is a medium-severity vulnerability in Fortinet IPS Engine, published on 10 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A interpretation conflict in Fortinet IPS Engine versions 7.321, 7.166 and 6.158 allows attacker to evade IPS features via crafted TCP packets.

Weakness: CWE-436 (Interpretation Conflict)

## Which versions are affected by CVE-2023-40718?

It affects 1 product.


Products: Fortinet Fortios Ips Engine.

## How do I fix CVE-2023-40718?

No fix has been published for CVE-2023-40718 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-40718 being exploited?

There is no known exploitation of CVE-2023-40718 in the wild and no public exploit code.

## Other vulnerabilities in Fortinet IPS Engine

- [CVE-2019-5592](https://insights.sbomify.com/CVE-2019-5592/): Information disclosure in Fortinet IPS Engine (medium 5.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-40718 and fix it if it is affected.

What it is: CVE-2023-40718 is a medium-severity vulnerability in Fortinet IPS Engine, published on 10 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-40718 in the wild and no public exploit code.

Affected product: Fortinet IPS Engine. 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-2023-40718/ (Markdown: https://insights.sbomify.com/CVE-2023-40718/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-40718
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-40718
- OSV: https://osv.dev/vulnerability/CVE-2023-40718

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-40718/
Summaries are generated and may contain mistakes; the official description above is the record.