CVE-2025-34314 is a stored cross-site scripting vulnerability affecting IPFire firewall software versions prior to 2.29 (Core Update 198). The vulnerability arises from improper neutralization of input during web page generation (CWE-79). Specifically, when an authenticated user creates a time constraint rule via an HTTP POST request to /cgi-bin/urlfilter.cgi with MODE=TIMECONSTRAINT, the parameters SRC (source hostnames/IPs), DST (destination), and COMMENT (remarks) are accepted. These parameters are stored and later rendered in the web interface without proper sanitization or encoding, allowing injected JavaScript code to execute in the context of other users who view the time constraint entries. Exploitation requires the attacker to be authenticated to the IPFire web interface but does not require elevated privileges. The attack vector is network-based, with low complexity, and user interaction is limited to viewing the malicious entry. The vulnerability could enable attackers to perform actions such as session hijacking, stealing credentials, or conducting further attacks within the victim's browser session. Although no known exploits are currently reported in the wild, the vulnerability poses a moderate risk due to the widespread use of IPFire in network security environments. The CVSS 4.0 score of 5.1 reflects these factors, indicating a medium severity level. Mitigation involves applying updates to IPFire 2.29 or later when available or implementing strict input validation and output encoding on affected parameters.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on IPFire as a perimeter firewall or network security appliance. Successful exploitation could allow attackers to execute arbitrary JavaScript in the context of administrative or user sessions, potentially leading to credential theft, session hijacking, or unauthorized actions within the IPFire management interface. This could compromise network security configurations, leading to broader network exposure or disruption. Given that IPFire is often used in small to medium enterprises and some public sector environments across Europe, exploitation could affect critical infrastructure, internal network segmentation, or security monitoring capabilities. The vulnerability's requirement for authentication limits exposure but does not eliminate risk, as insider threats or compromised credentials could be leveraged. The absence of known exploits in the wild reduces immediate risk but does not preclude targeted attacks. Organizations handling sensitive data or critical infrastructure should consider this vulnerability a moderate threat to confidentiality and integrity of network security controls.

European organizations should prioritize upgrading IPFire installations to version 2.29 (Core Update 198) or later once patches are released. Until then, administrators should restrict access to the IPFire web interface to trusted networks and users only, employing strong authentication mechanisms such as multi-factor authentication to reduce the risk of unauthorized access. Regularly audit user accounts and remove or disable unused accounts to minimize the attack surface. Implement network-level controls such as VPNs or IP whitelisting to limit management interface exposure. Additionally, monitor logs for unusual activity related to time constraint rule creation or modification. If possible, apply web application firewall (WAF) rules to detect and block suspicious payloads targeting the SRC, DST, and COMMENT parameters. Educate administrators about the risks of stored XSS and encourage cautious handling of input fields. Finally, prepare incident response plans to quickly address any suspected exploitation attempts.