CVE-2026-33765
Published: 27 March 2026
Summary
CVE-2026-33765 is a high-severity OS Command Injection (CWE-78) vulnerability in Pi-Hole Web Interface. Its CVSS base score is 8.9 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 39.0% of CVEs by exploit likelihood; 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).
Deeper analysis
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.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-16781
Vulnerability details
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
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).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation and sanitization of user-controlled inputs like the 'webtheme' parameter to prevent OS command injection in savesettings.php.
Mandates timely identification, reporting, and patching of flaws like this command injection vulnerability, as addressed in Pi-hole version 6.0.
Enforces least privilege to restrict sudo/root privileges for the PHP exec() process, limiting the scope of damage from injected commands.