CVE-2025-55280 is a medium-severity vulnerability affecting the ZKTeco WL20 Biometric Attendance System, specifically versions up to and including ZLM31-FXO1-3.1.8. The core issue is the cleartext storage of sensitive information—namely Wi-Fi credentials, configuration data, and system data—within the device firmware. This vulnerability is classified under CWE-312, which pertains to the improper storage of sensitive data in an unencrypted or plaintext format. An attacker with physical access to the device can extract the firmware and reverse engineer the binary data to retrieve this sensitive information. Access to Wi-Fi credentials can enable unauthorized network access, potentially allowing the attacker to infiltrate the internal network environment. Furthermore, the attacker could manipulate or retrieve data stored on the device, compromising the integrity and confidentiality of attendance records and system configurations. The CVSS 4.0 base score is 5.2, reflecting a medium severity level, with an attack vector requiring physical access (AV:P), low attack complexity (AC:L), no privileges or user interaction needed, but with high impact on confidentiality and low to limited impact on integrity and availability. No known exploits are currently reported in the wild, and no patches have been published yet. The vulnerability does not require network access or authentication but does require physical possession of the device, which limits the attack surface but still poses a significant risk in environments where devices are accessible to unauthorized personnel.

For European organizations, especially those deploying ZKTeco WL20 biometric attendance systems, this vulnerability poses a tangible risk to both network security and data integrity. Unauthorized access to Wi-Fi credentials could allow attackers to pivot into corporate networks, potentially accessing sensitive internal resources or launching further attacks. Manipulation of attendance data could disrupt HR processes, payroll, and compliance reporting, leading to operational and reputational damage. Given that biometric systems are often used in secure or regulated environments, the exposure of configuration and system data could also facilitate more sophisticated attacks or unauthorized surveillance. The requirement for physical access somewhat limits remote exploitation but does not eliminate risk in scenarios such as shared office spaces, maintenance activities, or insider threats. The medium severity rating suggests that while the vulnerability is not critical, it is sufficiently serious to warrant prompt attention, especially in sectors with stringent data protection requirements such as finance, healthcare, and government institutions within Europe.

European organizations should implement a multi-layered approach to mitigate this vulnerability. First, physical security controls must be strengthened to restrict unauthorized access to biometric attendance devices, including secure mounting, surveillance, and access logging. Second, organizations should monitor for firmware updates or patches from ZKTeco and apply them promptly once available. In the absence of patches, consider isolating the biometric devices on segmented network zones with strict access controls to limit lateral movement if credentials are compromised. Additionally, change Wi-Fi credentials regularly and use strong, unique passwords to reduce the window of opportunity for attackers. Employ network monitoring to detect unusual access patterns or unauthorized devices connecting to the network. Where possible, replace or upgrade devices that store sensitive data in plaintext with models that implement secure storage and encryption. Finally, conduct regular security audits and employee training to raise awareness about the risks of physical device tampering and insider threats.