# CVE-2021-33806: Deserialization in n/a

> Remote attackers can execute arbitrary code by sending malicious serialized data to applications using the BdLib library.

- **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:** 3 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-8ww6-p355-pvjq

## What is CVE-2021-33806?

CVE-2021-33806 is a critical unsafe deserialization vulnerability in n/a, published on 3 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The BDew BdLib library before 1.16.1.7 for Minecraft allows remote code execution because it deserializes untrusted data in ObjectInputStream.readObject as part of its use of Java serialization.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2021-33806?

It affects 1 product.


Products: Bdew Bdlib.

## How do I fix CVE-2021-33806?

No fix has been published for CVE-2021-33806 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-33806 being exploited?

There is no known exploitation of CVE-2021-33806 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-33806 and fix it if it is affected.

What it is: CVE-2021-33806 is a critical unsafe deserialization vulnerability in n/a, published on 3 Jun 2021. 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-2021-33806 in the wild and no public exploit code.

Affected product: n/a. 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-2021-33806/ (Markdown: https://insights.sbomify.com/CVE-2021-33806/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-33806
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-33806
- OSV: https://osv.dev/vulnerability/CVE-2021-33806

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-33806/
Summaries are generated and may contain mistakes; the official description above is the record.