# CVE-2019-5597: Security feature bypass in FreeBSD

> Malicious IPv6 packets can bypass packet filtering or crash the system due to a bug in FreeBSD's fragment reassembly logic.

- **Severity:** Critical 9.1 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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:** 15 May 2019
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-f2x6-v2r6-g94v

## What is CVE-2019-5597?

CVE-2019-5597 is a critical vulnerability in Freebsd Freebsd, published on 15 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In FreeBSD 11.3-PRERELEASE and 12.0-STABLE before r347591, 11.2-RELEASE before 11.2-RELEASE-p10, and 12.0-RELEASE before 12.0-RELEASE-p4, a bug in the pf IPv6 fragment reassembly logic incorrectly uses the last extension header offset from the last received packet instead of the first packet allowing maliciously crafted IPv6 packets to cause a crash or potentially bypass the packet filter.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2019-5597?

It affects 1 product.


Products: Freebsd Freebsd.

## How do I fix CVE-2019-5597?

No fix has been published for CVE-2019-5597 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-5597 being exploited?

There is no known exploitation of CVE-2019-5597 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-2019-5597 and fix it if it is affected.

What it is: CVE-2019-5597 is a critical vulnerability in Freebsd Freebsd, published on 15 May 2019. 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-2019-5597 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-2019-5597/ (Markdown: https://insights.sbomify.com/CVE-2019-5597/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-5597
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-5597
- OSV: https://osv.dev/vulnerability/CVE-2019-5597

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-5597/
Summaries are generated and may contain mistakes; the official description above is the record.