# CVE-2021-26814: Improper Input Validation (RCE)

> Authenticated users can execute arbitrary code with administrative privileges via incomplete input validation in the Wazuh API file management endpoint.

- **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:** Yes
- **Published:** 6 Mar 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-w36g-q975-37rg

## What is CVE-2021-26814?

CVE-2021-26814 is a high-severity code injection vulnerability in Wazuh Wazuh, published on 6 Mar 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Wazuh API in Wazuh from 4.0.0 to 4.0.3 allows authenticated users to execute arbitrary code with administrative privileges via /manager/files URI. An authenticated user to the service may exploit incomplete input validation on the /manager/files API to inject arbitrary code within the API service script.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2021-26814?

2 open source packages ship an affected version, including wazuh. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `wazuh` | npm | From 4.0.0 | 4.0.4 |
| `wazuh` | npm | From 4.0.0 | 4.0.4 |

Products: Wazuh Wazuh.

## How do I fix CVE-2021-26814?

Upgrade wazuh to 4.0.4 or later.

## Is CVE-2021-26814 being exploited?

There is no known exploitation of CVE-2021-26814 in the wild and no public exploit code.

Public exploit code:

- A simple python PoC to exploit CVE-2021-26814 and gain RCE on Wazuh Manager (v.4.0.0-4.0.3) through the API service. (github_poc): https://github.com/WickdDavid/CVE-2021-26814
- PoC of CVE-2021-26814 (github_poc): https://github.com/CYS4srl/CVE-2021-26814
- https://github.com/paolorabbito/Internet-Security-Project---CVE-2021-26814 (github_poc): https://github.com/paolorabbito/Internet-Security-Project---CVE-2021-26814

## Other vulnerabilities in Wazuh Wazuh

- [CVE-2025-24016](https://insights.sbomify.com/CVE-2025-24016/): Wazuh Server Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2024-32038](https://insights.sbomify.com/CVE-2024-32038/): Wazuh Analysis Engine Event Decoder Heap-based Buffer Overflow Remote Code Execution Vulnerability (critical 9.8)
- [CVE-2021-44079](https://insights.sbomify.com/CVE-2021-44079/): Command injection in n/a (critical 9.8)
- [CVE-2024-1243](https://insights.sbomify.com/CVE-2024-1243/): Remote code execution and local privilege escalation in Wazuh Windows agent via NetNTLMv2 hash theft (critical 9.5)
- [CVE-2026-61800](https://insights.sbomify.com/CVE-2026-61800/): Wazuh cluster worker file sync allows arbitrary file write under /var/ossec (incomplete fix for CVE-2026-30893) (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-26814 and fix it if it is affected.

What it is: CVE-2021-26814 is a high-severity code injection vulnerability in Wazuh Wazuh, published on 6 Mar 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-2021-26814 in the wild and no public exploit code.

Affected packages and fixed versions:
- wazuh (npm): affected from 4.0.0; fixed in 4.0.4
- wazuh (npm): affected from 4.0.0; fixed in 4.0.4

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-2021-26814/ (Markdown: https://insights.sbomify.com/CVE-2021-26814/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-26814
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-26814
- OSV: https://osv.dev/vulnerability/CVE-2021-26814

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-26814/
Summaries are generated and may contain mistakes; the official description above is the record.