# CVE-2018-6916: Use after free in FreeBSD

> A use-after-free vulnerability in the FreeBSD kernel IPsec AH handling code allows attackers to cause a system crash or unpredictable results.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Mar 2018
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-mvc8-6h45-px2q

## What is CVE-2018-6916?

CVE-2018-6916 is a critical use after free vulnerability in Freebsd Freebsd, published on 9 Mar 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In FreeBSD before 11.1-STABLE, 11.1-RELEASE-p7, 10.4-STABLE, 10.4-RELEASE-p7, and 10.3-RELEASE-p28, the kernel does not properly validate IPsec packets coming from a trusted host. Additionally, a use-after-free vulnerability exists in the IPsec AH handling code. This issue could cause a system crash or other unpredictable results.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2018-6916?

It affects 1 product.


Products: Freebsd Freebsd.

## How do I fix CVE-2018-6916?

No fix has been published for CVE-2018-6916 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-6916 being exploited?

There is no known exploitation of CVE-2018-6916 in the wild and no public exploit code.

## Other vulnerabilities in Freebsd Freebsd

- [CVE-2018-17160](https://insights.sbomify.com/CVE-2018-17160/): Memory corruption in FreeBSD (critical 10.0)
- [CVE-2014-3954](https://insights.sbomify.com/CVE-2014-3954/): Memory corruption in n/a (critical 10.0)
- [CVE-2006-4304](https://insights.sbomify.com/CVE-2006-4304/): Memory corruption in n/a (critical 10.0)
- [CVE-2006-0226](https://insights.sbomify.com/CVE-2006-0226/): Integer overflow in n/a (critical 10.0)
- [CVE-2004-0002](https://insights.sbomify.com/CVE-2004-0002/): Denial of service in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-6916 and fix it if it is affected.

What it is: CVE-2018-6916 is a critical use after free vulnerability in Freebsd Freebsd, published on 9 Mar 2018. 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-2018-6916 in the wild and no public exploit code.

Affected product: Freebsd Freebsd. 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-2018-6916/ (Markdown: https://insights.sbomify.com/CVE-2018-6916/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-6916
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-6916
- OSV: https://osv.dev/vulnerability/CVE-2018-6916

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-6916/
Summaries are generated and may contain mistakes; the official description above is the record.