CVE-2025-34175 is a medium severity reflected Cross-Site Scripting (XSS) vulnerability identified in Netgate's pfSense Community Edition (CE) version 7.0.8_2, specifically within the suricata_filecheck.php web interface component. The vulnerability arises because the 'filehash' parameter is directly reflected in the HTML response without proper sanitization or encoding of HTML-related characters. This improper neutralization of input (classified under CWE-79) allows an attacker to craft a malicious URL containing executable JavaScript code embedded in the 'filehash' parameter. When an authenticated user accesses this crafted URL, the malicious script executes in their browser context, potentially leading to session hijacking, unauthorized actions, or information disclosure within the pfSense web interface. The vulnerability does not require prior authentication to trigger the reflected XSS, but the victim must be authenticated for the attack to have impact. The CVSS 4.0 score of 5.1 reflects a network attack vector with low complexity and no privileges required, but user interaction is necessary, and the impact on confidentiality is low. No known exploits are currently reported in the wild, and no official patches have been linked yet. This vulnerability highlights a common web application security flaw where user-supplied input is not properly sanitized before being embedded in dynamic web pages, allowing script injection and execution in the context of a trusted web application.

For European organizations using pfSense CE 7.0.8_2 as their firewall or network security appliance, this vulnerability could allow attackers to execute malicious scripts in the context of the pfSense web management interface. Potential impacts include theft of administrative session tokens, unauthorized configuration changes, or redirection to malicious sites. Since pfSense is often deployed at network perimeters or critical network segments, compromise of the management interface could lead to broader network security breaches. The requirement that the victim be authenticated limits the attack surface to users with access to the pfSense web UI, typically network administrators or security personnel. However, phishing or social engineering could be used to lure such users into clicking malicious links. The reflected nature of the XSS means the attacker must convince the victim to visit a crafted URL, which could be delivered via email or other communication channels. While the direct impact on confidentiality and integrity is limited to the web interface session, successful exploitation could facilitate further attacks against the internal network. Given the widespread use of pfSense CE in European SMEs, educational institutions, and some enterprises, this vulnerability poses a tangible risk to the security of network infrastructure if not addressed promptly.

1. Immediate mitigation involves restricting access to the pfSense web interface to trusted networks and users only, using VPNs or IP whitelisting to reduce exposure. 2. Administrators should educate users about the risks of clicking untrusted links, especially those purporting to be related to pfSense management. 3. Implement web application firewall (WAF) rules to detect and block suspicious requests containing script payloads targeting the 'filehash' parameter. 4. Monitor pfSense web server logs for unusual or suspicious URL parameters that may indicate attempted exploitation. 5. Until an official patch is released, consider disabling or restricting access to the Suricata file check feature if feasible. 6. Once available, promptly apply vendor-supplied patches or updates addressing this vulnerability. 7. Conduct regular security audits and penetration testing of the pfSense management interface to detect similar input validation issues. 8. Employ Content Security Policy (CSP) headers on the pfSense web interface to limit the execution of injected scripts. These targeted mitigations go beyond generic advice by focusing on network access controls, user awareness, monitoring, and temporary feature restrictions specific to this vulnerability.