CVE-2026-20127
CRITICALCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Lifecycle Timeline
4Description
A vulnerability 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. 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.
Analysis
Cisco Catalyst SD-WAN Controller and Manager contain a critical authentication bypass (CVE-2026-20127, CVSS 10.0) in the peering authentication mechanism that allows unauthenticated remote attackers to obtain full administrative privileges. The vulnerability exists because peering authentication does not properly validate credentials, enabling any attacker with network access to take over the SD-WAN management plane and control the entire WAN fabric.
Sign in for full analysis, threat intelligence, and remediation guidance.
Remediation
Within 24 hours: Identify all Cisco SD-WAN Controller and Manager instances in your environment and isolate them to restricted network segments with strict access controls. Within 7 days: Implement continuous monitoring for unauthorized access attempts and administrative account changes; engage Cisco TAC for interim mitigation guidance specific to your deployment. …
Sign in for detailed remediation steps.
Priority Score
Share
External POC / Exploit Code
Leaving vuln.today