# CVE-2018-6331: Deserialization in Buck

> Maliciously crafted state files in Buck parser-cache can trigger code execution via unsafe Java deserialization.

- **Severity:** Critical 9.8 (`CVSS:3.1/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:** 31 Dec 2018
- **Updated:** 6 May 2025
- **Also known as:** GHSA-gwvw-v6hg-775r

## What is CVE-2018-6331?

CVE-2018-6331 is a critical unsafe deserialization vulnerability in Facebook Buck, published on 31 Dec 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Buck parser-cache command loads/saves state using Java serialized object. If the state information is maliciously crafted, deserializing it could lead to code execution. This issue affects Buck versions prior to v2018.06.25.01.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2018-6331?

It affects 1 product.


Products: Facebook Buck.

## How do I fix CVE-2018-6331?

No fix has been published for CVE-2018-6331 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-6331 being exploited?

There is no known exploitation of CVE-2018-6331 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-6331 and fix it if it is affected.

What it is: CVE-2018-6331 is a critical unsafe deserialization vulnerability in Facebook Buck, published on 31 Dec 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-2018-6331 in the wild and no public exploit code.

Affected product: Facebook Buck. 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-2018-6331/ (Markdown: https://insights.sbomify.com/CVE-2018-6331/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-6331
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-6331
- OSV: https://osv.dev/vulnerability/CVE-2018-6331

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-6331/
Summaries are generated and may contain mistakes; the official description above is the record.