CVE-2025-51651 is an authenticated arbitrary file download vulnerability found in the /admin/Backups.php component of Mccms version 2.7.0. This vulnerability allows an attacker who has valid authentication credentials to craft a specially designed GET request that can trigger the download of arbitrary files from the server hosting the vulnerable Mccms application. The vulnerability arises due to insufficient validation or sanitization of input parameters in the Backups.php script, which is responsible for handling backup-related operations in the admin panel. By exploiting this flaw, an attacker can access sensitive files outside the intended backup scope, potentially including configuration files, source code, database credentials, or other critical data stored on the server. Although exploitation requires authentication, the impact can be significant because it can lead to unauthorized disclosure of sensitive information, which may facilitate further attacks such as privilege escalation, lateral movement, or data exfiltration. The vulnerability is currently published but lacks a CVSS score and no known public exploits have been reported in the wild. The absence of a patch link suggests that a fix may not yet be available or publicly disclosed, increasing the urgency for affected organizations to implement compensating controls or monitor for suspicious activity. Given that Mccms is a content management system, the vulnerability primarily affects web servers running this specific version, and the attack vector is limited to authenticated users, which may include legitimate administrators or compromised accounts.

For European organizations using Mccms v2.7.0, this vulnerability poses a risk of sensitive data exposure, which can undermine confidentiality and potentially integrity if attackers leverage the obtained information to further compromise systems. The arbitrary file download capability can lead to leakage of critical files such as database credentials, private keys, or internal configuration files, enabling attackers to escalate privileges or pivot within the network. This is particularly concerning for organizations handling personal data under GDPR, as unauthorized data disclosure could result in regulatory penalties and reputational damage. The requirement for authentication reduces the attack surface but does not eliminate risk, especially if credential theft or weak authentication mechanisms exist. The lack of a patch means organizations must rely on detection and mitigation strategies until an official fix is released. Additionally, attackers could use this vulnerability as a stepping stone for more advanced attacks, increasing the overall threat level to European enterprises relying on Mccms for content management or web services.

1. Immediately restrict access to the /admin/Backups.php endpoint to only trusted administrators and limit authentication to strong, multi-factor methods to reduce the risk of credential compromise. 2. Implement strict input validation and sanitization at the web application firewall (WAF) or reverse proxy level to detect and block suspicious GET requests targeting file download parameters. 3. Monitor web server logs and application logs for unusual file download requests or access patterns indicative of exploitation attempts. 4. If possible, disable or restrict backup functionality temporarily until a patch is available. 5. Conduct a thorough audit of user accounts with administrative access to ensure no unauthorized users exist and enforce strong password policies. 6. Segregate the Mccms server from critical internal networks to limit lateral movement in case of compromise. 7. Stay updated with vendor advisories for patches or official mitigations and plan for prompt application once available. 8. Consider deploying file integrity monitoring to detect unauthorized changes or downloads of sensitive files. These steps go beyond generic advice by focusing on access control hardening, proactive detection, and network segmentation tailored to the specifics of this vulnerability.