CVE-2025-27845 is a vulnerability identified in the ESPEC North America Web Controller version 3 prior to 3.3.4. The flaw exists in the authentication API endpoint (/api/v4/auth/) where any invalid authentication request inadvertently exposes the JSON Web Token (JWT) secret key. JWT secrets are critical cryptographic keys used to sign and verify tokens that control user authentication and authorization within the web controller's UI. Exposure of this secret allows an attacker to forge or manipulate JWT tokens, thereby gaining elevated permissions within the user interface without proper authentication. This vulnerability effectively bypasses authentication controls, enabling unauthorized access and potential full control over the web controller's management interface. The vulnerability does not require valid credentials or user interaction, and no known exploits are currently reported in the wild. However, the impact of such a flaw is significant given the sensitive nature of industrial or environmental control systems managed by ESPEC controllers. The lack of a CVSS score indicates the need for an independent severity assessment based on the technical details provided.

For European organizations using ESPEC North America Web Controllers, this vulnerability poses a serious risk. These controllers are typically used in environmental testing, manufacturing, and industrial automation sectors, where unauthorized access could lead to manipulation of critical processes, data integrity loss, or operational disruptions. Attackers exploiting this flaw could escalate privileges, alter configurations, or disrupt services, potentially causing safety hazards or compliance violations under EU regulations such as GDPR or NIS Directive. The exposure of the JWT secret undermines the trustworthiness of the authentication mechanism, increasing the risk of lateral movement within networks. Given the industrial context, the impact extends beyond IT systems to physical processes, which is a significant concern for European industries reliant on precise environmental controls.

Immediate mitigation should include upgrading the ESPEC North America Web Controller to version 3.3.4 or later, where this vulnerability is addressed. If upgrading is not immediately feasible, organizations should implement network-level access controls to restrict access to the /api/v4/auth/ endpoint, limiting it to trusted IP addresses or VPN users only. Monitoring and logging authentication attempts should be enhanced to detect anomalous or repeated invalid authentication requests that could indicate exploitation attempts. Additionally, organizations should rotate any JWT secrets and related credentials post-patch to invalidate any potentially compromised tokens. Employing Web Application Firewalls (WAF) with custom rules to block suspicious API requests can provide an additional protective layer. Finally, conducting a thorough security audit of the affected systems and related infrastructure is recommended to identify any signs of compromise.