[CIVN-2026-0102] Authentication Bypass Vulnerability in CISCO

By Published On: February 27, 2026

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Authentication Bypass Vulnerability in CISCO


Indian – Computer Emergency Response Team (https://www.cert-in.org.in)



Severity Rating: CRITICAL


Software Affected


Cisco Catalyst SD-WAN Controller and Cisco Catalyst SD-WAN Manager

Overview


A vulnerability has been reported in the peering authentication in Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, and Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage could allow an unauthenticated, remote attacker to bypass authentication and obtain administrative privileges on an affected system.


Target Audience: 

All IT administrators and individuals responsible for maintaining and updating in Software.


Risk Assessment:

High risk of data manipulation and service disruption.


Impact Assessment:

Potential impact on confidentiality, integrity, and availability of the system.


Description


This vulnerability exists due to 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.


Successful exploitation of this vulnerability 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.


Solution


Apply appropriate updates as mentioned in Cisco Advisory

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa-EHchtZk



Vendor Information


CISCO

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa-EHchtZk


References


CISCO

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa-EHchtZk


CVE Name

CVE-2026-20127




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Thanks and Regards,

CERT-In


Incident Response Help Desk

e-mail: incident@cert-in.org.in

Phone: +91-11-22902657

Toll Free Number: 1800-11-4949

Toll Free Fax : 1800-11-6969

Web: http://www.cert-in.org.in

PGP Fingerprint: A768 083E 4475 5725 B81A A379 2156 C0C0 B620 D0B4

PGP Key information:

https://www.cert-in.org.in/s2cMainServlet?pageid=CONTACTUS


Postal address:

Indian Computer Emergency Response Team (CERT-In)

Ministry of Electronics and Information Technology

Government of India

Electronics Niketan

6, C.G.O. Complex

New Delhi-110 003

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