# CVE-2021-20089: Other in purl

> Prototype pollution in the purl library allows attackers to inject properties into Object.prototype, potentially leading to code execution or security bypasses.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-fc5x-mj45-vx78

## What is CVE-2021-20089?

CVE-2021-20089 is a high-severity vulnerability in purl, published on 23 Apr 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') in purl 2.3.2 allows a malicious user to inject properties into Object.prototype.

Weakness: CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes)

## Which versions are affected by CVE-2021-20089?

It affects 1 product.


Products: Purl Project Purl.

## How do I fix CVE-2021-20089?

No fix has been published for CVE-2021-20089 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20089 being exploited?

There is no known exploitation of CVE-2021-20089 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20089 and fix it if it is affected.

What it is: CVE-2021-20089 is a high-severity vulnerability in purl, published on 23 Apr 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-2021-20089 in the wild and no public exploit code.

Affected product: purl. 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-2021-20089/ (Markdown: https://insights.sbomify.com/CVE-2021-20089/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20089
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20089
- OSV: https://osv.dev/vulnerability/CVE-2021-20089

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20089/
Summaries are generated and may contain mistakes; the official description above is the record.