CVE-2026-33405

Pi-hole Admin Interface from 6.0 to before 6.5 places configuration values from the /api/config endpoint directly into HTML value="" attributes without escaping in settings-advanced.js, enabling HTML attribute injection. A double quote in any config value breaks out of the attribute context. JavaScript execution is blocked by the server's CSP (script-src 'self'), but injected attributes can alter element styling for UI redressing. The primary attack vector is importing a malicious teleporter backup, which bypasses per-field server-side validation.

In the Pi-hole Admin Interface, client hostnames and IP addresses from the FTL database are rendered into the DOM without escaping in network.js and charts.js/index.js. Although upstream validation in dnsmasq and FTL blocks HTML characters via normal DHCP/DNS paths, the web UI performs no output escaping, inconsistent with other fields. The vulnerability is fixed in 6.5.

Pi-hole Admin Interface versions 6.0 to before 6.5 contain a reflected DOM-based XSS vulnerability in taillog.js. An unauthenticated attacker can inject arbitrary HTML into the admin interface via a crafted URL because the file parameter is interpolated into innerHTML without escaping. The missing form-action directive in Content-Security-Policy allows injected forms to exfiltrate credentials. The vulnerability is fixed in 6.5.

Pi-hole Admin Interface before version 6.3 is vulnerable to CRLF injection. When a request is made to a file ending with the .lp extension, the application performs a redirect without proper input sanitization. An attacker can inject carriage return and line feed characters (%0d%0a) to manipulate both headers and content of the HTTP response, enabling injection of arbitrary HTTP response headers, potentially leading to session fixation, cache poisoning, and weakening or bypassing browser-based security mechanisms such as CSP or X-XSS-Protection.

Pi-hole Admin Interface versions 6.2.1 and earlier are vulnerable to reflected cross-site scripting (XSS) via a malformed URL path. The 404 error page includes the requested path in the class attribute of the body tag without proper sanitization or escaping.

Pi-hole Admin Interface versions prior to 6.3 are vulnerable to cross-site scripting (XSS) via the Address field in the Subscribed Lists group management section. An authenticated user can inject malicious JavaScript that executes when another user navigates to the Tools section and performs a gravity database update. The vulnerability is patched in version 6.3.