CVE-2026-20127CiscoRouters and networkingOctober 28, 2026

Cisco Catalyst SD-WAN Controller Authentication Bypass Vulnerability

Critical 10Actively exploited

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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa-EHchtZk Security Impact Rating: Critical CVE: CVE-2026-20127

What to do

Install the fixed versions listed in the official advisory. If you cannot update right away, apply the workarounds or mitigations it describes and limit access to the affected service.

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Details

Vendor
Cisco
Product
Cisco Catalyst SD-WAN
CVE
CVE-2026-20127
Affected versions
Cisco Catalyst SD-WAN Manager 20.1: 7 versions, from 20.1.1 to 20.1.12
Cisco Catalyst SD-WAN Manager 19.2: 14 versions, from 19.2.0 to 19.2.929
Cisco Catalyst SD-WAN Manager 18.4: 10 versions, from 18.4.0 to 18.4.501_ES
Cisco Catalyst SD-WAN Manager 19.3: 19.3.0
Cisco Catalyst SD-WAN Manager 18.3: 11 versions, from 18.3.0 to 18.3.8
Cisco Catalyst SD-WAN Manager 19.0: 19.0.0; 19.0.1a
Cisco Catalyst SD-WAN Manager 19.1: 19.1.0
Cisco Catalyst SD-WAN Manager 17.2: 7 versions, from 17.2.4 to 17.2.10
Cisco Catalyst SD-WAN Manager 18.2: 18.2.0
Cisco Catalyst SD-WAN Manager 20.3: 56 versions, from 20.3.1 to 20.3.814
Cisco Catalyst SD-WAN Manager 20.4: 20 versions, from 20.4.1 to 20.4.2.3
Cisco Catalyst SD-WAN Manager 20.5: 6 versions, from 20.5.0.1.1 to 20.5.1.2
Cisco Catalyst SD-WAN Manager 20.6: 74 versions, from 20.6.0.18.3 to 20.6.8
Cisco Catalyst SD-WAN Manager 20.7: 5 versions, from 20.7.1EFT2 to 20.7.2
Cisco Catalyst SD-WAN Manager 20.8: 20.8.1
Cisco Catalyst SD-WAN Manager 20.9: 64 versions, from 20.9.1EFT2 to 20.9.8_LI_Images
Cisco Catalyst SD-WAN Manager 20.10: 4 versions, from 20.10.1 to 20.10.1.2
Cisco Catalyst SD-WAN Manager 20.11: 4 versions, from 20.11.1 to 20.11.1.2
Cisco Catalyst SD-WAN Manager 20.12: 26 versions, from 20.12.1 to 20.12.501
Cisco Catalyst SD-WAN Manager 20.13: 20.13.1_LI_Images; 20.13.1
Cisco Catalyst SD-WAN Manager 20.14: 20.14.1; 20.14.1_LI_Images
Cisco Catalyst SD-WAN Manager 20.15: 11 versions, from 20.15.1_LI_Images to 20.15.4.1
Cisco Catalyst SD-WAN Manager 20.16: 20.16.1; 20.16.1_LI_Images
Cisco Catalyst SD-WAN Manager 20.18: 4 versions, from 20.18.1 to 20.18.2_LI_Images (from the advisory and NVD; check the exact builds in the official advisory)
CVSS score
10
Actively exploited
Yes, listed in the CISA Known Exploited Vulnerabilities catalog
Source
Cisco PSIRT – original advisory
Published
October 28, 2026

The description and the recommended action are quoted from the public advisory (the action is our generic advice); severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.

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