CVE-2026-20127: Cisco Catalyst SD-WAN Controller and Manager Authentication
Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass Vulnerability. Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, and Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, contain an authentication bypass vulnerability 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 an 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.
- CISA KEV-listed (remediation due 2026-02-27)
- EPSS 88.2% (99.8% percentile)
- CVSS 10 critical
Related briefings
- Hackers exploit a new Cisco SD-WAN zero-day to gain root access 2026-06-24
- CISA warns of two actively exploited Cisco and cPanel bugs 2026-06-16
- Hackers Break Into Unpatched Cisco SD-WAN Devices to Plant Webshells 2026-06-06
- CVE-2026-20127: Active Exploitation at Scale of Cisco Catalyst SD-WAN Zero-Day - Webshell Deployment, Sophisticated Implants, and 50+ Attack IPs Observed 2026-03-05