# CVE-2019-5596: Use after free in FreeBSD

> A use-after-free bug in FreeBSD UNIX domain sockets allows local attackers to gain root privileges or escape jails.

- **Severity:** High 8.8 (`CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Feb 2019
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-89xf-9vcr-5475

## What is CVE-2019-5596?

CVE-2019-5596 is a high-severity use after free vulnerability in Freebsd Freebsd, published on 12 Feb 2019. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In FreeBSD 11.2-STABLE after r338618 and before r343786, 12.0-STABLE before r343781, and 12.0-RELEASE before 12.0-RELEASE-p3, a bug in the reference count implementation for UNIX domain sockets can cause a file structure to be incorrectly released potentially allowing a malicious local user to gain root privileges or escape from a jail.

## Which versions are affected by CVE-2019-5596?

It affects 1 product.


Products: Freebsd Freebsd.

## How do I fix CVE-2019-5596?

No fix has been published for CVE-2019-5596 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-5596 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-5596 exists.

Public exploit code:

- Full LPE Exploit for CVE-2019-5596 / FreeBSD-SA-19:02.fd (github_poc): https://github.com/raymontag/CVE-2019-5596
- FreeBSD 12.0 - 'fd' Local Privilege Escalation (exploitdb)
- FreeBSD-SA-19:02.fd - Privilege Escalation (exploitdb)

## 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-2019-5596 and fix it if it is affected.

What it is: CVE-2019-5596 is a high-severity use after free vulnerability in Freebsd Freebsd, published on 12 Feb 2019. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-5596 exists.

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-2019-5596/ (Markdown: https://insights.sbomify.com/CVE-2019-5596/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-5596
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-5596
- OSV: https://osv.dev/vulnerability/CVE-2019-5596

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-5596/
Summaries are generated and may contain mistakes; the official description above is the record.