CVE intelligence and bounded remediation
CVE-2026-26953 — Pi-hole Admin Interface is a web interface for managing Pi-hole, a network-level ad and internet tracker blocking application
Pi-hole Admin Interface is a web interface for managing Pi-hole, a network-level ad and internet tracker blocking application. Versions 6.0 and above have a Stored HTML Injection vulnerability in the active sessions table located on the API settings page, allowing an attacker with valid credentials to inject arbitrary HTML code that will be rendered in the browser of any administrator who visits the active sessions page. The rowCallback function contains the value data.x_forwarded_for, which is directly concatenated into an HTML string and inserted into the DOM using jQuery’s .html() method. This method interprets the content as HTML, which means that any HTML tags present in the value will be parsed and rendered by the browser. An attacker can use common tools such as curl, wget, Python requests, Burp Suite, or even JavaScript fetch() to send an authentication request with an X-Forwarded-For header that contains malicious HTML code instead of a legitimate IP address. Since Pi-hole implements a Content Security Policy (CSP) that blocks inline JavaScript, the impact is limited to pure HTML injection without the ability to execute scripts. This issue has been fixed in version 6.4.1.
- Severity
- Medium
- CVSS
- 5.4 (3.1)
- Published
- 2026-02-19
- CISA KEV
- Not currently listed
- Ecosystem
- javascript/npm
- Weaknesses
- CWE-20, CWE-79, CWE-116
Affected products
- pi-hole / web_interface
Matched remediation archetype
Cross-site scripting and unsafe browser output
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
Check exposure
- Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
- Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
- Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.
Remediate safely
- Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
- Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
- Update affected rendering components and add tests for every output context using inert sentinel markup.
Authoritative sources
Complete CVE record and remediation plan
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