CVE-2025-56556 is a vulnerability identified in Subrion CMS version 4.2.1 that affects the built-in Run SQL Query feature accessible via the SQL Tool admin panel. This feature is intended for use by authenticated administrators or moderators to execute SQL queries directly on the underlying database. The vulnerability allows these authenticated users, who already have some level of administrative or moderation privileges, to escalate their privileges beyond their intended scope by exploiting the SQL query execution capability. Essentially, the flaw lies in insufficient access control or input validation within the SQL Tool, enabling privilege escalation within the CMS environment. Since the vulnerability requires authenticated access to the SQL Tool, it is not exploitable by unauthenticated attackers. However, once exploited, it could allow an attacker with limited admin or moderator rights to gain full administrative control or perform unauthorized actions within the CMS, potentially leading to unauthorized data access, modification, or disruption of service. No CVSS score has been assigned yet, and there are no known exploits in the wild or available patches at the time of publication. The vulnerability was reserved on August 17, 2025, and published on September 11, 2025.

For European organizations using Subrion CMS 4.2.1, this vulnerability poses a significant risk to the confidentiality, integrity, and availability of their web content and underlying data. An attacker with legitimate admin or moderator credentials could leverage this flaw to escalate privileges, potentially gaining full control over the CMS. This could lead to unauthorized data disclosure, defacement of websites, insertion of malicious content, or disruption of services hosted on the CMS. The impact is particularly critical for organizations that rely on Subrion CMS for public-facing websites, e-commerce platforms, or internal portals containing sensitive information. Given the requirement for authenticated access, the threat is more relevant in environments where user access controls are weak or where credential compromise is possible. The vulnerability could also facilitate lateral movement within an organization’s network if the CMS is integrated with other internal systems. European organizations with strict data protection regulations such as GDPR could face compliance and reputational risks if this vulnerability is exploited to leak personal or sensitive data.

To mitigate this vulnerability, European organizations should first verify whether they are running Subrion CMS version 4.2.1 and assess the usage of the SQL Tool admin panel. Immediate steps include restricting access to the SQL Tool feature strictly to the most trusted administrators and moderators, implementing the principle of least privilege for all CMS users, and monitoring usage logs for any unusual or unauthorized SQL query executions. Organizations should also consider disabling the Run SQL Query feature if it is not essential for daily operations. Since no official patch is available yet, organizations should engage with Subrion CMS developers or community forums to track the release of security updates addressing this issue. Additionally, enforcing strong authentication mechanisms such as multi-factor authentication (MFA) for all admin and moderator accounts can reduce the risk of credential compromise. Regular security audits and penetration testing focused on CMS components can help identify and remediate similar privilege escalation risks. Finally, network segmentation and web application firewalls (WAF) can provide additional layers of defense to limit the impact of a successful exploit.