CVE-2025-59151: pi-hole web CRLF Injection

Vulnerability summary

CVE-2025-59151 is a high (CVSS 8.2) CRLF Injection vulnerability in pi-hole web. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 36.5% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 27-10-2025
   PublishedVulnerability first disclosed.
2. 27-10-2025
   Last modifiedVulnerability information updated.

Description

Pi-hole Admin Interface is a web interface for managing Pi-hole, a network-level advertisement and internet tracker blocking application. Pi-hole Admin Interface before 6.3 is vulnerable to Carriage Return Line Feed (CRLF) injection. When a request is made to a file ending with the .lp extension, the application performs a redirect without properly sanitizing the input. An attacker can inject carriage return and line feed characters (%0d%0a) to manipulate both the headers and the content of the HTTP response. This enables the injection of arbitrary HTTP response headers, potentially leading to session fixation, cache poisoning, and the weakening or bypassing of browser-based security mechanisms such as Content Security Policy or X-XSS-Protection. This vulnerability is fixed in 6.3.

• CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.
• CWE-113Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')The product receives data from an HTTP agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers.