# CVE-2021-32706: (Authenticated) Remote Code Execution Possible in Web Interface 5.5

> Authenticated attackers can execute arbitrary code, list directories, and overwrite files via a regex flaw in the domain validation filter.

- **Severity:** High 7.6 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/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:** 4 Aug 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-5cm9-6p3m-v259

## What is CVE-2021-32706?

CVE-2021-32706 is a high-severity code injection vulnerability in pi-hole AdminLTE, published on 4 Aug 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Pi-hole's Web interface provides a central location to manage a Pi-hole instance and review performance statistics. Prior to Pi-hole Web interface version 5.5.1, the `validDomainWildcard` preg_match filter allows a malicious character through that can be used to execute code, list directories, and overwrite sensitive files. The issue lies in the fact that one of the periods is not escaped, allowing any character to be used in its place. A patch for this vulnerability was released in version 5.5.1.

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

## Which versions are affected by CVE-2021-32706?

It affects 1 product.


Products: Pi-Hole Pi-Hole.

## How do I fix CVE-2021-32706?

No fix has been published for CVE-2021-32706 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-32706 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-32706 exists.

Public exploit code:

- Pi-Hole Top Domains API Authenticated Exec (metasploit)

## Other vulnerabilities in pi-hole AdminLTE

- [CVE-2020-8816](https://insights.sbomify.com/CVE-2020-8816/): Pi-Hole AdminLTE Remote Code Execution (critical 9.1, exploited in the wild)
- [CVE-2025-34087](https://insights.sbomify.com/CVE-2025-34087/): Pi-Hole AdminLTE Whitelist (now 'Web Allowlist') Remote Command Execution (critical 9.0)
- [CVE-2026-50130](https://insights.sbomify.com/CVE-2026-50130/): Pi-hole: Local privilege escalation from `pihole` user to root via `/etc/pihole/logrotate` (high 8.8)
- [CVE-2020-11108](https://insights.sbomify.com/CVE-2020-11108/): File upload in n/a (high 8.8)
- [CVE-2019-13051](https://insights.sbomify.com/CVE-2019-13051/): Pi-Hole 4.3 allows Command Injection. (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-32706 and fix it if it is affected.

What it is: CVE-2021-32706 is a high-severity code injection vulnerability in pi-hole AdminLTE, published on 4 Aug 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-32706 exists.

Affected product: pi-hole AdminLTE. 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-2021-32706/ (Markdown: https://insights.sbomify.com/CVE-2021-32706/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-32706
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-32706
- OSV: https://osv.dev/vulnerability/CVE-2021-32706

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-32706/
Summaries are generated and may contain mistakes; the official description above is the record.