Shaun Crampton

**Name of the Vulnerable Software and Affected Versions** Calico Typha versions 3.26.2 and below Calico Typha version 3.25.1 Calico Enterprise Typha versions 3.17.1 and below Calico Enterprise Typha version 3.16.3 Calico Enterprise Typha version 3.15.3 **Description** The issue arises when a client TLS handshake can block the Calico Typha server indefinitely, resulting in denial of service. This occurs because the TLS Handshake() call is performed inside the main server handle for loop without any timeout, allowing an unclean TLS handshake to block the main loop indefinitely while other connections will be idle waiting for that handshake to finish. **Recommendations** For Calico Typha versions 3.26.2 and below, consider implementing a timeout for the TLS handshake to prevent indefinite blocking. For Calico Typha version 3.25.1, consider implementing a timeout for the TLS handshake to prevent indefinite blocking. For Calico Enterprise Typha versions 3.17.1 and below, consider implementing a timeout for the TLS handshake to prevent indefinite blocking. For Calico Enterprise Typha version 3.16.3, consider implementing a timeout for the TLS handshake to prevent indefinite blocking. For Calico Enterprise Typha version 3.15.3, consider implementing a timeout for the TLS handshake to prevent indefinite blocking.