# CVE-2021-39235: Access mode of block tokens are not enforced

> Authenticated users with read-only block tokens can perform unauthorized write operations on data blocks in Apache Ozone.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Nov 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-c6j7-4fr9-c76p

## What is CVE-2021-39235?

CVE-2021-39235 is a medium-severity missing authorization vulnerability in Apache Ozone, published on 19 Nov 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

In Apache Ozone before 1.2.0, Ozone Datanode doesn't check the access mode parameter of the block token. Authenticated users with valid READ block token can do any write operation on the same block.

Weakness: CWE-732 (Incorrect Permission Assignment for Critical Resource)

## Which versions are affected by CVE-2021-39235?

2 open source packages ship an affected version, including org.apache.ozone:ozone-main. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.apache.ozone:ozone-main` | Maven | All versions | 1.2.0 |
| `org.apache.ozone:ozone-main` | Maven | All versions | 1.2.0 |

Products: Apache Ozone.

## How do I fix CVE-2021-39235?

Upgrade org.apache.ozone:ozone-main to 1.2.0 or later.

## Is CVE-2021-39235 being exploited?

There is no known exploitation of CVE-2021-39235 in the wild and no public exploit code.

## Other vulnerabilities in Apache Ozone

- [CVE-2021-36372](https://insights.sbomify.com/CVE-2021-36372/): Original block tokens are persisted and can be retrieved (critical 9.8)
- [CVE-2021-39231](https://insights.sbomify.com/CVE-2021-39231/): Missing authentication/authorization on internal RPC endpoints (critical 9.1)
- [CVE-2021-39233](https://insights.sbomify.com/CVE-2021-39233/): Container-related datanode operations can be called without authorization (critical 9.1)
- [CVE-2021-39232](https://insights.sbomify.com/CVE-2021-39232/): Missing admin check for SCM related admin commands (high 8.8)
- [CVE-2021-39236](https://insights.sbomify.com/CVE-2021-39236/): Owners of the S3 tokens are not validated (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-39235 and fix it if it is affected.

What it is: CVE-2021-39235 is a medium-severity missing authorization vulnerability in Apache Ozone, published on 19 Nov 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-39235 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.apache.ozone:ozone-main (Maven): affected all versions; fixed in 1.2.0
- org.apache.ozone:ozone-main (Maven): affected all versions; fixed in 1.2.0

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-2021-39235/ (Markdown: https://insights.sbomify.com/CVE-2021-39235/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-39235
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-39235
- OSV: https://osv.dev/vulnerability/CVE-2021-39235

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-39235/
Summaries are generated and may contain mistakes; the official description above is the record.