CVE-2026-24933 is a vulnerability classified under CWE-295 (Improper Certificate Validation) affecting ASUSTOR ADM network-attached storage (NAS) devices. The root cause lies in the API communication component's failure to properly validate SSL/TLS certificates when establishing HTTPS connections to the server. This improper validation allows an unauthenticated remote attacker to conduct Man-in-the-Middle (MitM) attacks by intercepting and manipulating network traffic between the ADM device and its server. Exploitation can lead to exposure of sensitive user information transmitted in cleartext, including account email addresses, MD5 hashed passwords, and device serial numbers. The affected versions span from ADM 4.1.0 through 4.3.3.ROF1 and 5.0.0 through 5.1.1.RCI1, covering multiple major releases. The vulnerability is remotely exploitable without requiring authentication or user interaction, increasing its risk profile. The CVSS 4.0 base score of 8.9 reflects a high severity due to the network attack vector, low attack complexity, and high impact on confidentiality. Although no public exploits have been reported, the vulnerability poses a significant threat to the confidentiality and integrity of data managed by ASUSTOR ADM devices. The improper certificate validation undermines the fundamental security guarantees of TLS, making communications vulnerable to interception and data leakage. Organizations relying on ASUSTOR ADM for critical data storage and management should prioritize remediation to prevent potential data breaches and subsequent attacks leveraging exposed credentials or device information.

For European organizations, this vulnerability presents a substantial risk of sensitive data exposure, including user credentials and device identifiers, which can facilitate further attacks such as unauthorized access, lateral movement, or targeted espionage. Given that ASUSTOR ADM devices are commonly used for centralized data storage and backup in enterprises, government agencies, and critical infrastructure sectors, exploitation could lead to significant confidentiality breaches and operational disruptions. The exposure of MD5 hashed passwords, while not plaintext, still poses a risk as MD5 is considered weak and susceptible to cracking, potentially allowing attackers to escalate privileges. Additionally, compromised device serial numbers may aid attackers in fingerprinting and targeting specific assets. The lack of authentication or user interaction required for exploitation increases the likelihood of successful attacks, especially in environments with inadequate network segmentation or monitoring. European organizations with remote or cloud-managed ASUSTOR ADM deployments are particularly vulnerable to MitM attacks if network traffic is not properly secured. The potential impact extends beyond data loss to include reputational damage, regulatory penalties under GDPR for inadequate data protection, and increased attack surface for follow-on intrusions.

1. Apply official patches or firmware updates from ASUSTOR as soon as they become available to address the certificate validation flaw. 2. Until patches are deployed, restrict network access to ASUSTOR ADM devices by implementing strict firewall rules and network segmentation to limit exposure to untrusted networks. 3. Employ network-level encryption and VPNs to protect communications between ADM devices and management servers, reducing the risk of MitM attacks. 4. Monitor network traffic for unusual patterns or signs of interception, such as unexpected certificate changes or anomalous HTTPS connections. 5. Replace or upgrade weak hashing algorithms used for password storage, moving away from MD5 to stronger algorithms like bcrypt or Argon2, if configurable. 6. Conduct regular security audits and penetration tests focusing on NAS devices and their communication channels. 7. Educate IT staff about the risks of improper certificate validation and the importance of verifying TLS certificates in all networked applications. 8. Implement multi-factor authentication (MFA) for ADM device access to mitigate risks from credential exposure. 9. Maintain an inventory of all ASUSTOR ADM devices and their firmware versions to ensure timely patch management. 10. Consider deploying intrusion detection/prevention systems (IDS/IPS) capable of detecting MitM attack signatures on critical network segments.