# CVE-2021-47688: Race condition in WhiteBeam

> A local attacker can bypass allow-list restrictions by exploiting a race condition between file truncation and verification actions.

- **Severity:** Medium 5.7 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Jun 2025
- **Updated:** 24 Jun 2025
- **Also known as:** GHSA-3f8r-9483-pfxj, GHSA-fjgv-863q-h54r

## What is CVE-2021-47688?

CVE-2021-47688 is a medium-severity vulnerability in WhiteBeam, published on 23 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In WhiteBeam 0.2.0 through 0.2.1 before 0.2.2, a user with local access to a server can bypass the allow-list functionality because a file can be truncated in the OpenFileDescriptor action before the VerifyCanWrite action is performed.

Weakness: CWE-696 (Incorrect Behavior Order)

## Which versions are affected by CVE-2021-47688?


## How do I fix CVE-2021-47688?

No fix has been published for CVE-2021-47688 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-47688 being exploited?

There is no known exploitation of CVE-2021-47688 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-47688 and fix it if it is affected.

What it is: CVE-2021-47688 is a medium-severity vulnerability in WhiteBeam, published on 23 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-47688 in the wild and no public exploit code.

Affected product: WhiteBeam. 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-2021-47688/ (Markdown: https://insights.sbomify.com/CVE-2021-47688/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47688
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47688
- OSV: https://osv.dev/vulnerability/CVE-2021-47688

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47688/
Summaries are generated and may contain mistakes; the official description above is the record.