CVE-2026-33765

CriticalRCE

Published: 27 March 2026

Published

27 March 2026

Modified

07 April 2026

KEV Added

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Patch

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CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0024 46.8th percentile

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

Summary

CVE-2026-33765 is a critical-severity OS Command Injection (CWE-78) vulnerability in Pi-Hole Web Interface. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 46.8th 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 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-10 Information Input Validation good match

prevent

Directly requires validation and sanitization of user-controlled inputs like the 'webtheme' parameter to prevent OS command injection in savesettings.php.

SI-2 Flaw Remediation good match

prevent

Mandates timely identification, reporting, and patching of flaws like this command injection vulnerability, as addressed in Pi-hole version 6.0.

AC-6 Least Privilege partial match

prevent

Enforces least privilege to restrict sudo/root privileges for the PHP exec() process, limiting the scope of damage from injected commands.

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 →

T1059.004 Unix Shell Execution

Adversaries may abuse Unix shell commands and scripts for execution.

attack.mitre.org →

Why these techniques?

CVE enables unauthenticated remote exploitation of a public-facing web application (T1190) via OS command injection, facilitating arbitrary Unix shell command execution as root (T1059.004).

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

NVD Description

Pi-hole Admin Interface is a web interface for managing Pi-hole, a network-level ad and internet tracker blocking application. Versions prior to 6.0 have a critical OS Command Injection vulnerability in the savesettings.php file. The application takes the user-controlled $_POST['webtheme'] parameter…

and concatenates it directly into a system command executed via PHP's exec() function. Since the input is neither sanitized nor validated before being passed to the shell, an attacker can append arbitrary system commands to the intended pihole command. Furthermore, because the command is executed with sudo privileges, the injected commands will run with elevated (likely root) privileges. Version 6.0 patches the issue.

Deeper analysisAI

CVE-2026-33765 is a critical OS Command Injection vulnerability (CWE-78) in the Pi-hole Admin Interface, the web interface for managing Pi-hole, a network-level ad and internet tracker blocking application. It affects versions prior to 6.0 and resides in the savesettings.php file, where the user-controlled $_POST['webtheme'] parameter is directly concatenated into a system command executed via PHP's exec() function without any sanitization or validation. This allows attackers to append arbitrary system commands to the intended pihole command. The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

An unauthenticated remote attacker can exploit this vulnerability by submitting a crafted HTTP POST request to the savesettings.php endpoint with a malicious 'webtheme' value that injects arbitrary OS commands. Because the command executes with sudo privileges, likely as root, successful exploitation grants the attacker full remote code execution with elevated privileges, enabling complete system compromise including data theft, persistence, or further lateral movement.

The official advisory from the Pi-hole web repository at https://github.com/pi-hole/web/security/advisories/GHSA-828h-5x96-rqx7 describes the vulnerability in detail, and version 6.0 of the Pi-hole Admin Interface patches the issue by addressing the insecure command construction.