CVE-2026-20182

Mapping is CWE-to-CAPEC per MITRE CAPEC 3.9.

May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and fixed after the was disclosed in February 2026. This new advisory is for a new vulnerability in the control connection handshaking. The section of this advisory includes Show Control Connections guidance to help with system checks.  A vulnerability in the peering authentication in Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, and Cisco Catalyst SD-WAN Validator, formerly SD-WAN vBond, could allow an unauthenticated, remote attacker to bypass authentication and obtain administrative privileges on an affected system. This vulnerability exists because the peering authentication mechanism in an affected system is not working properly. An attacker could exploit this vulnerability by sending crafted requests to the affected system. A successful exploit could allow the attacker to log in to an affected Cisco Catalyst SD-WAN Controller as an internal, high-privileged, non-root user account. Using this account, the attacker could access NETCONF, which would then allow the attacker to manipulate network configuration for the SD-WAN fabric.

Source: NIST NVD / MITRE CVE Database

Remediation Priority: IMMEDIATE

Implement strict network segmentation and access controls to limit exposure to the affected systems. Monitor network traffic for unusual activity and apply the latest vendor patches immediately.

No reliable network detection signature exists for this vulnerability class — apply the compensating controls above and the vendor patch. SAGE only publishes a network rule when a concrete on-the-wire signature can be grounded in the advisory.

Virtual patch generated by CITED Relevance SAGE. Validate in isolated environment before production deployment. Compensating control only - does not replace vendor patch.