Improper authentication in Catalyst SD-WAN Controller (formerly SD-WAN vSmart) and Catalyst SD-WAN Manager (formerly SD-WAN vManage) - CVE-2026-20127

CSH
CYBERSECURITY HELP
Sign In REGISTER
 
Main Vulnerability Database Vulnerabilities #VU123273

Improper authentication in Catalyst SD-WAN Controller (formerly SD-WAN vSmart) and Catalyst SD-WAN Manager (formerly SD-WAN vManage) - CVE-2026-20127

Published: February 25, 2026 / Updated: April 2, 2026


Vulnerability identifier: #VU123273
CSH Severity: Critical
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-20127
CWE-ID: CWE-287
Exploitation vector: Remote access
Exploit availability: The vulnerability is being exploited in the wild

Vulnerability details

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to an error in authentication mechanism. A remote non-authenticated attacker can send specially crafted requests to bypass authentication process and access NETCONF, which would then allow to manipulate network configuration for the SD-WAN fabric.

Note, the vulnerability is being actively exploited in the wild. 


Affected software

Catalyst SD-WAN Controller (formerly SD-WAN vSmart)
Catalyst SD-WAN Manager (formerly SD-WAN vManage)

How to mitigate CVE-2026-20127

Install updates from vendor's website.

Catalyst SD-WAN Controller (formerly SD-WAN vSmart) - addressed in versions 20.9.8.2, 20.12.5.3, 20.12.6.1, 20.15.4.2, 20.18.2.1
Catalyst SD-WAN Manager (formerly SD-WAN vManage) - addressed in versions 20.9.8.2, 20.12.5.3, 20.12.6.1, 20.15.4.2, 20.18.2.1

Links to Public Exploits and PoC-codes

External References

Related Security Bulletins