# CVE-2021-37626: PHP file inclusion via insert tags

> Untrusted back end users can execute arbitrary PHP code via insert tags in the Contao CMS, requiring specific user permissions to exploit.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Aug 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-r6mv-ppjc-4hgr

## What is CVE-2021-37626?

CVE-2021-37626 is a high-severity code injection vulnerability in contao, published on 11 Aug 2021. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Contao is an open source CMS that allows you to create websites and scalable web applications. In affected versions it is possible to load PHP files by entering insert tags in the Contao back end. Installations are only affected if they have untrusted back end users who have the rights to modify fields that are shown in the front end. Update to Contao 4.4.56, 4.9.18 or 4.11.7 to resolve. If you cannot update then disable the login for untrusted back end users.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2021-37626?

12 open source packages ship an affected version, including contao/contao and contao/core-bundle. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `contao/contao` | Packagist | From 4.0.0 | 4.4.56 |
| `contao/contao` | Packagist | From 4.0.0 | 4.4.56 |
| `contao/contao` | Packagist | From 4.10.0 | 4.11.7 |
| `contao/contao` | Packagist | From 4.10.0 | 4.11.7 |
| `contao/contao` | Packagist | From 4.5.0 | 4.9.18 |
| `contao/contao` | Packagist | From 4.5.0 | 4.9.18 |
| `contao/core-bundle` | Packagist | From 4.0.0 | 4.4.56 |
| `contao/core-bundle` | Packagist | From 4.0.0 | 4.4.56 |
| `contao/core-bundle` | Packagist | From 4.10.0 | 4.11.7 |
| `contao/core-bundle` | Packagist | From 4.10.0 | 4.11.7 |
| `contao/core-bundle` | Packagist | From 4.5.0 | 4.9.18 |
| `contao/core-bundle` | Packagist | From 4.5.0 | 4.9.18 |

Products: Contao Contao.

## How do I fix CVE-2021-37626?

Upgrade contao/contao to a fixed version for your release line: 4.4.56, 4.11.7 or 4.9.18.

## Is CVE-2021-37626 being exploited?

There is no known exploitation of CVE-2021-37626 in the wild and no public exploit code.

## Other vulnerabilities in contao

- [CVE-2022-26265](https://insights.sbomify.com/CVE-2022-26265/): Remote Code Execution in Contao Managed Edition (critical 9.8)
- [CVE-2019-11512](https://insights.sbomify.com/CVE-2019-11512/): Contao SQL injection in the file manager (critical 9.8)
- [CVE-2012-4383](https://insights.sbomify.com/CVE-2012-4383/): Contao core SQL Injection Vulnerability (high 8.8)
- [CVE-2019-19745](https://insights.sbomify.com/CVE-2019-19745/): Unrestricted file uploads in Contao (high 8.8)
- [CVE-2024-28235](https://insights.sbomify.com/CVE-2024-28235/): Contao possible cookie sharing with external domains while checking protected pages for broken links (high 8.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-37626 and fix it if it is affected.

What it is: CVE-2021-37626 is a high-severity code injection vulnerability in contao, published on 11 Aug 2021. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-37626 in the wild and no public exploit code.

Affected packages and fixed versions:
- contao/contao (Packagist): affected from 4.0.0; fixed in 4.4.56
- contao/contao (Packagist): affected from 4.0.0; fixed in 4.4.56
- contao/contao (Packagist): affected from 4.10.0; fixed in 4.11.7
- contao/contao (Packagist): affected from 4.10.0; fixed in 4.11.7
- contao/contao (Packagist): affected from 4.5.0; fixed in 4.9.18
- contao/contao (Packagist): affected from 4.5.0; fixed in 4.9.18
- contao/core-bundle (Packagist): affected from 4.0.0; fixed in 4.4.56
- contao/core-bundle (Packagist): affected from 4.0.0; fixed in 4.4.56
- contao/core-bundle (Packagist): affected from 4.10.0; fixed in 4.11.7
- contao/core-bundle (Packagist): affected from 4.10.0; fixed in 4.11.7
- contao/core-bundle (Packagist): affected from 4.5.0; fixed in 4.9.18
- contao/core-bundle (Packagist): affected from 4.5.0; fixed in 4.9.18

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-2021-37626/ (Markdown: https://insights.sbomify.com/CVE-2021-37626/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-37626
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-37626
- OSV: https://osv.dev/vulnerability/CVE-2021-37626

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-37626/
Summaries are generated and may contain mistakes; the official description above is the record.