CVE-2023-41378: Tigera Calico Cloud

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

In certain conditions for Calico Typha (v3.26.2, v3.25.1 and below), and Calico Enterprise Typha (v3.17.1, v3.16.3, v3.15.3 and below), a client TLS handshake can block the Calico Typha server indefinitely, resulting in denial of service. 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.

Affected products

• Tigera Calico Cloud: before 18.0.0 (fixed in 18.0.0)
• Tigera Calico Enterprise: before 3.15.4 (fixed in 3.15.4); from 3.16.0, before 3.16.4 (fixed in 3.16.4); from 3.17.0, before 3.17.2 (fixed in 3.17.2)
• Tigera Calico OS: before 3.25.2 (fixed in 3.25.2); from 3.26.0, before 3.26.3 (fixed in 3.26.3)

Published 2023-11-06. Last modified 2026-06-17.