CVE-2026-26952: pi-hole web Improper Input Validation

Vulnerability summary

CVE-2026-26952 is a medium (CVSS 5.4) Improper Input Validation vulnerability in pi-hole web. EPSS estimates a 0.40% chance of exploitation in the next 30 days, higher than 33% of scored vulnerabilities.

Timeline

1. 19-02-2026
   PublishedVulnerability first disclosed.
2. 20-02-2026
   Last modifiedVulnerability information updated.

Description

Pi-hole Admin Interface is a web interface for managing Pi-hole, a network-level ad and internet tracker blocking application. Versions 6.4 and below are vulnerable to stored HTML injection through the local DNS records configuration page, which allows an authenticated administrator to inject code that is stored in the Pi-hole configuration and rendered every time the DNS records table is viewed. The populateDataTable() function contains a data variable with the full DNS record value exactly as entered by the user and returned by the API. This value is inserted directly into the data-tag HTML attribute without any escaping or sanitization of special characters. When an attacker supplies a value containing double quotes ("), they can prematurely “close” the data-tag attribute and inject additional HTML attributes into the element. Since Pi-hole implements a Content Security Policy (CSP) that blocks inline JavaScript, the impact is limited. This issue has been fixed in version 6.4.1.

• CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
• CWE-116Improper Encoding or Escaping of OutputThe product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.