# CVE-2026-35521: Pi-hole FTL affected by Remote Code Execution (RCE) via dhcp.hosts Newline Injection

> An authenticated attacker can inject dnsmasq directives via newline characters in DHCP hosts to execute arbitrary commands on the Pi-hole server.

- **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:** 7 Apr 2026
- **Updated:** 7 Apr 2026
- **Also known as:** GHSA-vfmq-jrx3-wv3c

## What is CVE-2026-35521?

CVE-2026-35521 is a high-severity command injection vulnerability in pi-hole FTL, published on 7 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

FTLDNS (pihole-FTL) provides an interactive API and also generates statistics for Pi-hole's Web interface. From 6.0 to before 6.6, the Pi-hole FTL engine contains a Remote Code Execution (RCE) vulnerability in the DHCP hosts configuration parameter (dhcp.hosts). This vulnerability allows an authenticated attacker to inject arbitrary dnsmasq configuration directives through newline characters, ultimately achieving command execution on the underlying system. This vulnerability is fixed in 6.6.

Weakness: CWE-93 (Improper Neutralization of CRLF Sequences), CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2026-35521?

It affects 1 product.


Products: Pi-Hole Ftldns.

## How do I fix CVE-2026-35521?

No fix has been published for CVE-2026-35521 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-35521 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-35521 exists.

## Other vulnerabilities in pi-hole FTL

- [CVE-2026-35517](https://insights.sbomify.com/CVE-2026-35517/): Pi-hole FTL affected by Remote Code Execution (RCE) via dns.upstreams Newline Injection (high 8.8)
- [CVE-2026-35518](https://insights.sbomify.com/CVE-2026-35518/): Pi-hole FTL affected by Remote Code Execution (RCE) via dns.cnameRecords Newline Injection (high 8.8)
- [CVE-2026-35519](https://insights.sbomify.com/CVE-2026-35519/): Pi-hole FTL affected by Remote Code Execution (RCE) via dns.hostRecord Newline Injection (high 8.8)
- [CVE-2026-35520](https://insights.sbomify.com/CVE-2026-35520/): Pi-hole FTL affected by Remote Code Execution (RCE) via dhcp.leaseTime Newline Injection (high 8.8)
- [CVE-2026-39849](https://insights.sbomify.com/CVE-2026-39849/): Pi-hole FTL remote code execution via newline injection in dns.interface configuration (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-35521 and fix it if it is affected.

What it is: CVE-2026-35521 is a high-severity command injection vulnerability in pi-hole FTL, published on 7 Apr 2026. 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-2026-35521 exists.

Affected product: pi-hole FTL. 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-2026-35521/ (Markdown: https://insights.sbomify.com/CVE-2026-35521/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-35521
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-35521
- OSV: https://osv.dev/vulnerability/CVE-2026-35521

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-35521/
Summaries are generated and may contain mistakes; the official description above is the record.