CVE-2025-34310 is a stored cross-site scripting (XSS) vulnerability identified in IPFire, an open-source firewall distribution widely used for network security. The vulnerability exists in versions prior to 2.29 (Core Update 198) and arises from improper neutralization of input during web page generation, specifically in the Quality of Service (QoS) configuration interface. Authenticated users can exploit this flaw by injecting malicious JavaScript code into the INC_SPD, OUT_SPD, DEFCLASS_INC, and DEFCLASS_OUT parameters via HTTP POST requests to /cgi-bin/qos.cgi when updating QoS settings. These parameters are stored and later rendered in the web interface without adequate sanitization or encoding, enabling the execution of injected scripts in the browsers of other users who access the QoS configuration pages. The vulnerability requires the attacker to have valid credentials (authenticated access) but does not require additional user interaction beyond viewing the affected pages. The CVSS 4.0 vector indicates network attack vector, low attack complexity, no privileges required beyond authentication, and no user interaction needed, with limited scope and impact confined to confidentiality and integrity. While no public exploits are currently known, the vulnerability poses risks such as session hijacking, credential theft, or unauthorized actions within the IPFire management interface. This flaw highlights the importance of input validation and output encoding in web applications, especially in administrative interfaces of security-critical products like firewalls.

For European organizations deploying IPFire as part of their network security infrastructure, this vulnerability could lead to unauthorized execution of malicious scripts within the administrative web interface. Potential impacts include session hijacking of administrators, theft of sensitive credentials, unauthorized configuration changes, and possible lateral movement within the network if attackers leverage the compromised interface. Given that IPFire is often used in small to medium enterprises and some public sector environments across Europe, exploitation could disrupt network security management and lead to broader compromise. The requirement for authenticated access limits the attack surface but insider threats or compromised credentials could enable exploitation. The vulnerability could also undermine trust in network security controls and increase the risk of data breaches or service disruptions. Organizations with remote or multi-administrator setups are particularly at risk if attackers can inject scripts that execute in other administrators’ browsers. Although no known exploits exist currently, the medium severity rating and the critical role of IPFire in network defense warrant proactive mitigation to prevent potential exploitation.

1. Upgrade IPFire installations to version 2.29 (Core Update 198) or later, where this vulnerability is fixed. 2. If immediate upgrade is not possible, restrict access to the IPFire web interface to trusted networks and users only, minimizing exposure to authenticated attackers. 3. Enforce strong authentication mechanisms and regularly audit user accounts to prevent unauthorized access. 4. Implement web application firewall (WAF) rules to detect and block suspicious POST requests targeting the QoS parameters (INC_SPD, OUT_SPD, DEFCLASS_INC, DEFCLASS_OUT). 5. Educate administrators to avoid clicking on suspicious links or performing QoS updates from untrusted devices. 6. Monitor logs for unusual QoS configuration changes or repeated POST requests to /cgi-bin/qos.cgi. 7. Consider isolating the management interface from general user networks to reduce risk of cross-site scripting impact. 8. Apply Content Security Policy (CSP) headers if configurable in IPFire to limit script execution origins. These targeted steps go beyond generic advice by focusing on access control, monitoring, and specific parameter filtering relevant to this vulnerability.