Authentication Bypass Vulnerability Affecting Cisco Catalyst SD-WAN Controller and Manager

Cisco Catalyst SD-WAN Controller and Cisco Catalyst SD-WAN Manager are solutions that provide centralized management of network policies and configurations in SD-WAN architectures. These solutions are affected by a critical vulnerability labeled CVE-2026-20127, which results from an insufficiency in the identity verification system between equipment. Exploitation of this vulnerability would allow an unauthenticated attacker to send specially crafted authentication requests to bypass authentication and gain privileged access to network administration and management interfaces. It is classified critical with a severity score of 10.0 according to CVSS v3.1.

• Cisco Catalyst SD-WAN Controller and Manager versions earlier than 20.9.8.2;
• Cisco Catalyst SD-WAN Controller and Manager version 20.12.6 and versions 20.11 through 20.12.5.3;
• Cisco Catalyst SD-WAN Controller and Manager versions 20.13 through 20.15.4.2;
• Cisco Catalyst SD-WAN Controller and Manager versions 20.16 through 20.18.2.1;

RECOMMENDED ACTIONS:

• Update Cisco Catalyst SD-WAN Controller and Manager to one of the versions below or later:;
• 20.9.8.2;
• 20.12.6.1;
• 20.12.5.3;
• 20.15.4.2;
• 20.18.2.1;
• restrict access to management interfaces to only trusted IP addresses;