CVE-2025-7099 is a deserialization vulnerability identified in BoyunCMS versions up to 1.21 running on PHP7. The vulnerability resides in the installation handler component, specifically within the file install/install2.php. It is triggered by manipulation of the 'db_host' argument, which leads to unsafe deserialization of data. Deserialization vulnerabilities occur when untrusted input is deserialized without proper validation, potentially allowing attackers to execute arbitrary code, escalate privileges, or cause denial of service. In this case, the vulnerability can be exploited remotely without authentication or user interaction, but the attack complexity is rated as high, indicating that exploitation requires significant skill or conditions. The CVSS 4.0 base score is 6.3 (medium severity), reflecting limited impact on confidentiality, integrity, and availability (all low), no privileges required, no user interaction, but high attack complexity. No known exploits are currently observed in the wild, but public disclosure of the exploit code exists, increasing the risk of future exploitation. The vulnerability affects all BoyunCMS versions from 1.0 through 1.21, which suggests a long-standing issue in the installation process. The lack of available patches at the time of publication means that affected users must rely on mitigation strategies until official fixes are released. Given that BoyunCMS is a content management system, exploitation could allow attackers to compromise websites, inject malicious content, or pivot into internal networks depending on deployment context.

For European organizations using BoyunCMS, this vulnerability poses a moderate risk. Successful exploitation could lead to unauthorized code execution on web servers, potentially compromising website integrity and availability. This could result in data breaches, defacement, or service disruption, impacting business reputation and compliance with regulations such as GDPR. Since the vulnerability is in the installation handler, it may primarily affect systems undergoing installation or reconfiguration, but if accessible on production systems, it could be leveraged by attackers remotely without authentication. The medium CVSS score indicates limited but non-negligible impact. Organizations relying on BoyunCMS for public-facing websites or internal portals should be aware of the risk, especially if they have not updated or hardened their installations. The high attack complexity reduces the likelihood of widespread exploitation but does not eliminate targeted attacks, particularly against high-value targets or sectors with sensitive data. The absence of known exploits in the wild currently limits immediate impact but public exploit disclosure increases future risk.

1. Immediately restrict access to the installation directory (install/) on production servers to prevent remote exploitation. This can be done via web server configuration (e.g., .htaccess, nginx rules) or network segmentation. 2. Monitor web server logs for suspicious requests targeting install/install2.php or unusual manipulation of the 'db_host' parameter. 3. Disable or remove the installation handler files from production environments once installation is complete to eliminate the attack surface. 4. Apply strict input validation and sanitization on all parameters, especially those involved in deserialization processes. 5. If possible, upgrade to a patched version of BoyunCMS once available. Until then, consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block exploit attempts targeting this vulnerability. 6. Conduct security audits and penetration tests focusing on deserialization and input handling vulnerabilities. 7. Educate development and operations teams about the risks of insecure deserialization and secure coding practices. 8. Implement network-level protections such as IP whitelisting or VPN access for administrative interfaces to reduce exposure.