CVE-2025-57055 is a Server-Side Request Forgery (SSRF) vulnerability identified in WonderCMS version 3.5.0. The vulnerability exists in the custom module installation functionality where an authenticated administrator can supply a malicious URL through the pluginThemeUrl POST parameter. The server-side code uses curl_exec() to fetch the URL without adequate validation or sanitization. This flaw allows an attacker with administrative privileges to coerce the server into making arbitrary HTTP requests to internal or external systems. SSRF vulnerabilities are particularly dangerous because they can be leveraged to access internal network resources that are otherwise inaccessible from the outside, potentially exposing sensitive information or enabling further attacks such as port scanning, internal service exploitation, or pivoting within the network. Since exploitation requires authentication as an administrator, the attack surface is limited to users with elevated privileges. However, given that administrators typically have broad access, the impact can be significant. The lack of a CVSS score indicates that this vulnerability is newly published and has not yet been fully assessed or exploited in the wild. The absence of patch links suggests that a fix may not yet be available, emphasizing the need for immediate mitigation steps. WonderCMS is a lightweight content management system used for website management, and version 3.5.0 is specifically affected. The vulnerability was reserved on August 17, 2025, and published on September 17, 2025.

For European organizations using WonderCMS 3.5.0, this SSRF vulnerability poses a considerable risk, especially for those with internal services or sensitive infrastructure behind firewalls. An attacker who compromises or already has administrative access to the CMS can exploit this flaw to perform unauthorized internal network reconnaissance, access metadata services, or reach internal APIs and databases that are not exposed externally. This can lead to data leakage, unauthorized access to internal systems, or facilitate lateral movement within the network. Organizations in sectors such as finance, healthcare, government, and critical infrastructure are particularly at risk due to the sensitivity of their internal networks and data. Additionally, since the vulnerability requires administrative authentication, the risk is heightened if credential compromise or insider threats exist. The potential for SSRF to bypass network segmentation and firewall rules can undermine perimeter defenses, making this vulnerability a serious concern for European entities that rely on WonderCMS for web content management.

1. Immediate mitigation should focus on restricting administrative access to trusted personnel only and enforcing strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of credential compromise. 2. Network-level controls should be implemented to restrict outbound HTTP requests from the CMS server to only necessary destinations, using egress filtering and firewall rules to prevent arbitrary external or internal requests. 3. Administrators should monitor logs for unusual or unexpected outbound requests originating from the CMS server, which may indicate exploitation attempts. 4. Until an official patch is released, consider disabling the custom module installation feature or restricting its use to prevent exploitation. 5. Conduct a thorough review of internal network services to ensure that sensitive endpoints are not unnecessarily exposed or accessible from the CMS server. 6. Once available, promptly apply security patches or updates from WonderCMS addressing this vulnerability. 7. Educate administrators about the risks of SSRF and the importance of validating URLs and inputs within administrative interfaces.