A significant security vulnerability has been identified in the HPE Telco Service Activator, which could potentially permit attackers to bypass access controls. Detailed in a security bulletin released on February 19, 2026, this flaw is due to a weakness in the Undertow HTTP server core utilized by the product.
Understanding the Vulnerability
The core issue lies in improper input validation within the server, particularly concerning the Host header in incoming HTTP requests. This defect can have serious implications, as many applications and gateways depend on the Host header to implement security measures, such as allowlists and request routing.
Designated as CVE-2025-12543, this vulnerability has been rated with a CVSS v3.1 base score of 9.6, marking it as critical. It affects all versions of the HPE Telco Service Activator prior to version 10.5.0. The flaw allows for potential unauthorized access by bypassing host-based restrictions.
Impact and Risk Assessment
The vulnerability’s network vector and lack of required privileges mean it can be exploited remotely without authentication. However, exploitation may necessitate some form of user interaction, such as clicking a malicious link or executing a specific request path.
Organizations using vulnerable versions of the HPE Telco Service Activator are at risk, especially if their systems are exposed to untrusted networks. The security flaw underscores the importance of maintaining up-to-date software to protect critical infrastructure.
Mitigation and Prevention Strategies
HPE advises customers to upgrade to the latest version of the Telco Service Activator to resolve this issue. In the meantime, restricting system access to VPNs or administrative networks can help mitigate risk until patching is complete.
Additional protective measures include enforcing stringent host allowlists on reverse proxies and closely monitoring web and application logs for irregular Host header values and unexpected routing patterns.
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