# CVE-2021-32827: Arbitrary code execution in MockServer

> An attacker can execute arbitrary code on a developer's machine by tricking them into visiting a malicious site while running MockServer with default settings.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 16 Aug 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-v3cg-h3f6-2242

## What is CVE-2021-32827?

CVE-2021-32827 is a medium-severity code injection vulnerability in Oracle Communications Cloud Native Core Policy, published on 16 Aug 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

MockServer is open source software which enables easy mocking of any system you integrate with via HTTP or HTTPS. An attacker that can trick a victim into visiting a malicious site while running MockServer locally, will be able to run arbitrary code on the MockServer machine. With an overly broad default CORS configuration MockServer allows any site to send cross-site requests. Additionally, MockServer allows you to create dynamic expectations using Javascript or Velocity templates. Both engines may allow an attacker to execute arbitrary code on-behalf of MockServer. By combining these two issues (Overly broad CORS configuration + Script injection), an attacker could serve a malicious page so that if a developer running MockServer visits it, they will get compromised. For more details including a PoC see the referenced GHSL-2021-059.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation), CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2021-32827?

2 open source packages ship an affected version, including org.mock-server:mockserver. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.mock-server:mockserver` | Maven | All versions to 5.11.2 | None |
| `org.mock-server:mockserver` | Maven | All versions to 5.11.2 | None |

Products: Mock-Server Mockserver, Oracle Communications Cloud Native Core Policy.

## How do I fix CVE-2021-32827?

No fix has been published for CVE-2021-32827 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-32827 being exploited?

There is no known exploitation of CVE-2021-32827 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-32827 and fix it if it is affected.

What it is: CVE-2021-32827 is a medium-severity code injection vulnerability in Oracle Communications Cloud Native Core Policy, published on 16 Aug 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-32827 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.mock-server:mockserver (Maven): affected all versions up to 5.11.2; no fix listed
- org.mock-server:mockserver (Maven): affected all versions up to 5.11.2; no fix listed

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-2021-32827/ (Markdown: https://insights.sbomify.com/CVE-2021-32827/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-32827
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-32827
- OSV: https://osv.dev/vulnerability/CVE-2021-32827

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-32827/
Summaries are generated and may contain mistakes; the official description above is the record.