CVE-2025-53533 Scanner

The Pi-hole Admin Interface is primarily used by network administrators and technology enthusiasts to block advertisements and improve security within a network. It operates as a local DNS sinkhole, providing network-level protection, which is particularly beneficial for educational institutions, small businesses, and households aiming for ad-free browsing experiences. The software is often installed on Raspberry Pi devices and other low-power hardware, making it economical and widely accessible. By using Pi-hole, users are empowered to enhance their network management capabilities, protect their privacy, and minimize bandwidth consumption. The interface offers an easy-to-understand dashboard that allows non-technical users to effectively manage and monitor their network activity in real-time. Many network advantages, such as user-friendly reporting and simplified device control, make it highly popular among its users.

Cross-Site Scripting (XSS) vulnerabilities emerge when data entered by users is not properly sanitized by a web application, leading to the execution of arbitrary scripts by the end-user. In the context of the Pi-hole Admin Interface, this vulnerability affects the 404-error page, where input is reflected into the HTML without proper sanitization. Such vulnerabilities are dangerous as they could allow attackers to execute scripts in the victim's browser environment. This may result in unauthorized actions being performed on behalf of the victim or the inadvertent disclosure of sensitive information such as authentication tokens, session identifiers, or cookies. Given the range of potential impacts, XSS remains one of the most prevalent and significant vulnerabilities affecting web applications.

The vulnerability in the Pi-hole Admin Interface is specifically located on the 404-error page, where user-supplied URL paths are inserted directly into the `class` attribute of the `body` tag. Since the input is not sanitized prior to being rendered on the page, attackers can craft malicious URLs to include arbitrary script code. When these URLs are processed, the script embedded in the URL is executed within the victim's browser in the context of the Pi-hole Admin Interface. The CVE-2025-53533 affects interfaces running version 6.2.1 or earlier, requiring network operators to update to mitigate this vulnerability. This issue underscores the critical importance of input validation and output encoding in web applications to guard against XSS attacks.

Exploitation of this XSS vulnerability can lead to several adverse effects, particularly compromising the integrity and confidentiality of data processed within the victim's browser. Attackers can steal sensitive content from active sessions, such as cookies or session history, enabling them to impersonate the user or hijack their session. By executing arbitrary JavaScript, malicious actors could also deliver payloads to exploit further vulnerabilities, potentially escalating their control over both the device and network. In environments where substantial trust is placed in the Pi-hole interface, successful exploitation could lead to unauthorized DNS entries or traffic rerouting, further exposing affected networks to a broader range of threats. Vigilance and timely remediation are thus imperative to prevent potential harm.

REFERENCES

• https://github.com/pi-hole/web/security/advisories/GHSA-w8f8-92rx-4f6w
• https://nvd.nist.gov/vuln/detail/CVE-2025-53533