CVE-2025-34308 is a stored cross-site scripting (XSS) vulnerability identified in IPFire, an open-source firewall and security distribution. The flaw exists in versions prior to 2.29 (Core Update 198) within the web interface's handling of the UPDATE_VALUE parameter on the Time Server configuration page. When an authenticated user updates the default time synchronization settings, the application sends an HTTP POST request to /cgi-bin/time.cgi with the UPDATE_VALUE parameter. This parameter's value is stored without proper input sanitization or output encoding, allowing malicious JavaScript code to be injected and persistently stored. When other users access the affected Time Server page, the injected script executes in their browser context, potentially enabling session hijacking, credential theft, or unauthorized actions within the IPFire management interface. The vulnerability requires the attacker to be authenticated but does not require elevated privileges, and user interaction is necessary to trigger the malicious script. The CVSS 4.0 score of 5.1 reflects a medium severity, considering the network attack vector, low attack complexity, no privileges required, but requiring user interaction. No public exploit code or active exploitation has been reported to date. The vulnerability stems from improper neutralization of input during web page generation (CWE-79), a common web security weakness. IPFire users should be aware that this vulnerability could be leveraged in targeted attacks against network administrators or internal users managing firewall configurations.

For European organizations, the impact of CVE-2025-34308 can be significant in environments where IPFire is deployed as a critical network security appliance. Successful exploitation could allow attackers to execute arbitrary scripts in the context of administrative users, potentially leading to session hijacking, theft of credentials, or unauthorized changes to firewall configurations. This could compromise network security, allowing further lateral movement or data exfiltration. Since IPFire is often used in small to medium enterprises and some public sector networks across Europe, the vulnerability could affect the integrity and availability of network defenses. The requirement for attacker authentication limits remote exploitation but insider threats or compromised credentials could be leveraged. The stored nature of the XSS means the malicious payload persists, increasing risk over time. Although no known exploits are active, the medium severity rating and the critical role of IPFire in network security warrant prompt attention to prevent escalation of attacks or targeted intrusions within European organizations.

To mitigate CVE-2025-34308, organizations should upgrade IPFire installations to version 2.29 (Core Update 198) or later, where the vulnerability is addressed. If immediate patching is not feasible, restrict access to the IPFire web interface to trusted networks and users only, employing strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of attacker authentication. Network segmentation should isolate management interfaces from general user access. Administrators should audit and monitor the Time Server configuration page for suspicious or unexpected entries in the UPDATE_VALUE parameter. Implement web application firewalls (WAFs) with rules to detect and block malicious script injections targeting the IPFire interface. Additionally, educate administrators about the risks of stored XSS and encourage regular credential rotation and session management best practices. Logging and alerting on configuration changes can help detect exploitation attempts early. Finally, consider deploying endpoint protection on administrative workstations to detect malicious scripts executed via the browser.