CVE-2025-4260 is a medium-severity deserialization vulnerability affecting the youkefu product developed by zhangyanbo2007, specifically versions 4.0, 4.1, and 4.2.0. The vulnerability exists in the impsave function within the TemplateController.java file located at m\web\handler\admin\system\. The issue arises from unsafe deserialization of the dataFile argument, which can be manipulated by an attacker to execute arbitrary code or cause other unintended behaviors. This vulnerability can be exploited remotely without requiring user interaction or authentication, as indicated by the CVSS vector (AV:N/AC:L/AT:N/UI:N/PR:L). The vulnerability has been publicly disclosed, but no known exploits are currently observed in the wild. The CVSS 4.0 base score is 5.3, reflecting a medium severity level. The vulnerability impacts confidentiality to a low degree, with no direct impact on integrity or availability noted. The attack complexity is low, and the attacker requires low privileges (PR:L), meaning some level of access to the system is needed but no user interaction or elevated privileges are required. The lack of patches or mitigation links suggests that a fix may not yet be available, increasing the urgency for organizations to implement compensating controls. Deserialization vulnerabilities are critical because they can allow remote code execution if exploited successfully, depending on the deserialized objects and the application context. In this case, the vulnerability is limited by the requirement of low privileges and the limited impact on integrity and availability, but it still poses a significant risk if exploited in sensitive environments.

For European organizations, the impact of CVE-2025-4260 depends on the deployment of the youkefu product within their IT infrastructure. youkefu is a customer service or helpdesk software, so organizations using it may face risks of unauthorized code execution or data manipulation if the vulnerability is exploited. This could lead to unauthorized access to customer data, disruption of customer support services, or lateral movement within the network. Given the medium severity and the requirement for low privileges, attackers who have gained some access could leverage this vulnerability to escalate their control or persist within the environment. In sectors with strict data protection regulations such as GDPR, any compromise of customer data or service availability could lead to regulatory penalties and reputational damage. Additionally, the lack of known exploits in the wild currently provides a window for mitigation before widespread exploitation occurs. However, organizations should act proactively to prevent potential attacks, especially those in critical infrastructure, finance, healthcare, or government sectors where customer support platforms are integral to operations.

1. Immediate mitigation should focus on restricting access to the vulnerable impsave function and the TemplateController endpoint, limiting it to trusted administrators only. 2. Implement network-level controls such as firewall rules or web application firewalls (WAF) to block or monitor suspicious requests targeting the deserialization functionality. 3. Conduct a thorough audit of user privileges to ensure that only necessary personnel have low-level privileges that could be leveraged to exploit this vulnerability. 4. If possible, disable or sandbox deserialization features or replace them with safer serialization mechanisms that validate input before deserialization. 5. Monitor logs for unusual activity related to the dataFile parameter or TemplateController access patterns. 6. Engage with the vendor or community to obtain patches or updates as soon as they become available and apply them promptly. 7. Consider implementing runtime application self-protection (RASP) solutions that can detect and block deserialization attacks in real time. 8. Educate administrators and developers about the risks of unsafe deserialization and secure coding practices to prevent similar vulnerabilities in the future.