CVE-2026-35517

HighRCE

Published: 07 April 2026

Published

07 April 2026

Modified

08 April 2026

KEV Added

—

Patch

—

CVSS Score 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0013 31.6th percentile

Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-35517 is a high-severity OS Command Injection (CWE-78) vulnerability. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 31.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 3 other techniques. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Directly mitigates the RCE vulnerability by requiring timely installation of the fix in Pi-hole FTL version 6.6.

SI-10 Information Input Validation good match

prevent

Prevents exploitation by validating and sanitizing the dns.upstreams input parameter to block newline injection and arbitrary dnsmasq directives.

CM-5 Access Restrictions for Change partial match

prevent

Limits the attack surface by restricting and documenting authorized changes to critical configuration settings like dns.upstreams.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1068 Exploitation for Privilege Escalation Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.

attack.mitre.org →

T1210 Exploitation of Remote Services Lateral Movement

Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.

attack.mitre.org →

T1059.004 Unix Shell Execution

Adversaries may abuse Unix shell commands and scripts for execution.

attack.mitre.org →

Why these techniques?

RCE via authenticated remote command injection in Pi-hole FTL API enables exploitation of public-facing web application (T1190), remote services (T1210), privilege escalation (T1068), and Unix shell execution (T1059.004).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

NVD 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 upstream DNS servers configuration parameter (dns.upstreams). 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.

Deeper analysisAI

CVE-2026-35517 is a remote code execution (RCE) vulnerability in the Pi-hole FTL engine, also known as FTLDNS, which provides an interactive API and generates statistics for Pi-hole's web interface. Affecting versions from 6.0 up to but not including 6.6, the flaw resides in the upstream DNS servers configuration parameter (dns.upstreams). It enables injection of arbitrary dnsmasq configuration directives via newline characters, leading to command execution on the underlying system. The vulnerability is associated with CWE-78 (OS Command Injection) and CWE-93 (Improper Neutralization of CRLF Sequences), and carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

An authenticated attacker with low privileges (PR:L) can exploit this vulnerability remotely over the network with low complexity and no user interaction required. By crafting a malicious payload in the dns.upstreams parameter, the attacker injects dnsmasq directives that execute arbitrary commands on the host system, potentially granting full control including high confidentiality, integrity, and availability impacts.

The official advisory on GitHub (GHSA-23w8-7333-p9fj) confirms the issue is resolved in Pi-hole FTL version 6.6, recommending immediate upgrades to mitigate the risk. No additional workarounds are specified in the provided details.