CVE DatabaseCVE-2026-20127

Updated 2026-06-17한국어 권고문 →

CVE-2026-2012710.0/CRITICALCISA KEVCWE-287

Cisco Catalyst SD-WAN Authentication Bypass and Admin Privilege Escalation (CVE-2026-20127) Critical Security Advisory

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Affected Vendors

cisco

Affected Components

catalyst sd-wan controller, catalyst sd-wan manager, catalyst sd-wan validator

Published Date

2026-02-25

CVSS v3.1

10.0

CRITICAL

EPSS (30d)

87.6%

FIRST.org

CISA KEV

Exploited

NVD Source ↗

Executive & SecOps Summary

SECOPS ASSESSMENT

Affected Scope

Cisco Catalyst SD-WAN Controller (formerly vSmart), Cisco Catalyst SD-WAN Manager (formerly vManage), and Cisco Catalyst SD-WAN Validator (formerly vBond).

Impact

Unauthenticated remote attackers can bypass peering authentication, gain high-privileged administrative access, and manipulate the entire SD-WAN fabric configuration via NETCONF.

Mitigation

Apply official Cisco software patches immediately and restrict control plane access to trusted peer IPs using Access Control Lists (ACLs).

Affected Products & Version Scope

All deployments of Cisco Catalyst SD-WAN Controller, Manager, and Validator running vulnerable software versions where peering authentication is enabled.

Remediation & Live Workaround Commands

PATCH & WORKAROUND

1. Official Patch & Version Upgrade Commands

Administrators should immediately upgrade to the patched software releases recommended by Cisco. Below are sample commands to install and activate the secure image via the CLI.

bash

# Download and install the secure software image on SD-WAN Manager
request software install repository:viptela-edge-secure-upgrade.tar.gz

# Activate the secure version and reboot the system
request software activate 20.x.x.x

2. Temporary Workaround & Hardening Configuration

If immediate patching is not feasible, restrict access to the control plane interfaces (specifically NETCONF and control ports) using localized ACLs to permit only authorized peer IPs.

bash

# Apply control plane ACL to restrict NETCONF (port 830) and control connections
policy
 access-list control-plane-policy
  sequence 10
   match
    source-ip 10.0.0.0/8
    destination-port 830 12346
   action accept
  sequence 20
   match
    source-ip 0.0.0.0/0
    destination-port 830 12346
   action drop
!

3. Log Audit & IoC Verification Commands

Run the following commands to inspect active sessions and search syslog files for unauthorized peering attempts or unexpected NETCONF configurations.

bash

# Check active administrative and user sessions
show user sessions

# Search syslog for peering authentication anomalies and NETCONF access logs
show log syslog | include 'NETCONF|peering|auth-fail'

# Verify the currently active software version
show software

Interactive SecOps Remediation Checklist

0/4 (0%)

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Technical Root Cause & Exploitation Mechanics

1. Vulnerability Overview & Root Cause

A critical vulnerability (CVE-2026-20127) exists in the peering authentication mechanism of Cisco Catalyst SD-WAN solutions. Due to improper validation of peering requests (CWE-287), the system fails to correctly verify the identity of connecting components, allowing an unauthenticated remote attacker to bypass authentication controls entirely.

2. Exploitation Mechanics & Attack Scenario

An attacker can exploit this vulnerability by sending specially crafted authentication requests to the affected SD-WAN controller. Because the peering authentication mechanism is flawed, the controller accepts the request and grants the attacker access as an internal, high-privileged, non-root user account. Using this established session, the attacker can connect to the NETCONF service and execute arbitrary configuration changes across the SD-WAN fabric.

3. Infrastructure & Business Impact

With a CVSS score of 10.0 and active exploitation confirmed by its inclusion in the CISA KEV catalog, this vulnerability poses an extreme risk to enterprise infrastructure. Successful exploitation allows complete control over the SD-WAN fabric, enabling attackers to intercept or reroute enterprise network traffic, perform Man-in-the-Middle (MitM) attacks, or cause widespread network outages.

Official Vendor Advisories & References

NVD Original English Description

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 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. 

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

Source: psirt@cisco.com · Vendor Advisory

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20127

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0 · US Government Resource

Frequently Asked SecOps Questions (CVE-2026-20127)

FAQ

Q1. How critical is CVE-2026-20127 and is it actively exploited in the wild?

CVE-2026-20127 is rated CVSS 10.0 (CRITICAL) with a 30-day EPSS exploitation probability of 87.6%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.

Q2. Which vendors and products are affected by CVE-2026-20127?

Primary impacted vendors include cisco across catalyst sd-wan controller, catalyst sd-wan manager, catalyst sd-wan validator. Scope summary: All deployments of Cisco Catalyst SD-WAN Controller, Manager, and Validator running vulnerable software versions where peering authentication is enabled.

Q3. What temporary mitigations or workarounds exist for CVE-2026-20127 before patching?

[Mitigation] Apply official Cisco software patches immediately and restrict control plane access to trusted peer IPs using Access Control Lists (ACLs). Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.

SECOPS WORKBENCH INTEGRATION