CVE-2025-65602 is a critical security vulnerability identified in ChanCMS version 3.3.4, specifically within the /vip/v1/file/save API endpoint. The vulnerability is a template injection flaw, which occurs when user-supplied input is improperly handled within server-side templates, allowing attackers to inject and execute arbitrary code. By crafting a malicious POST request targeting this endpoint, an attacker can exploit this flaw to execute arbitrary commands on the server hosting ChanCMS. This type of vulnerability is particularly dangerous because it can lead to full system compromise, enabling attackers to manipulate data, pivot within the network, or deploy malware. The vulnerability was reserved on November 18, 2025, and published on December 10, 2025, but currently lacks a CVSS score and no public exploits have been reported. The absence of a patch link indicates that a fix may not yet be available, increasing the urgency for organizations to implement temporary mitigations. The vulnerability does not specify affected versions beyond 3.3.4, but it is prudent to assume all prior versions are vulnerable. Template injection vulnerabilities typically arise from unsafe template rendering practices, such as unsanitized input being passed directly into template engines. This vulnerability requires no authentication, making it exploitable remotely by unauthenticated attackers, increasing its risk profile.

For European organizations, the impact of CVE-2025-65602 can be severe. Successful exploitation could lead to arbitrary code execution on web servers running ChanCMS 3.3.4, resulting in full compromise of the affected system. This can lead to data breaches, defacement of websites, disruption of services, and potential lateral movement within corporate networks. Organizations relying on ChanCMS for content management, especially those with public-facing portals or sensitive data, face risks to confidentiality, integrity, and availability. The lack of authentication requirement lowers the barrier for attackers, increasing the likelihood of exploitation. Additionally, the absence of a patch at the time of disclosure means organizations must rely on compensating controls, which may not fully mitigate the risk. The impact is heightened for sectors such as government, finance, healthcare, and critical infrastructure providers in Europe, where data protection regulations like GDPR impose strict requirements on data security and breach notification.

1. Immediate mitigation should focus on restricting access to the /vip/v1/file/save endpoint via network controls such as IP whitelisting or VPN access to limit exposure. 2. Deploy web application firewalls (WAFs) with custom rules to detect and block suspicious POST requests targeting this endpoint, especially those containing template syntax or unusual payloads. 3. Implement strict input validation and sanitization on all user inputs processed by ChanCMS, particularly those interacting with template engines. 4. Monitor server logs and network traffic for anomalous activity indicative of exploitation attempts. 5. Engage with ChanCMS vendors or community to obtain patches or updates addressing this vulnerability as soon as they become available. 6. Consider isolating or sandboxing the affected CMS environment to limit potential damage in case of exploitation. 7. Conduct security audits and penetration testing focused on template injection and related vulnerabilities in the CMS environment. 8. Educate development and operations teams about secure template handling practices to prevent future occurrences.