CVE-2026-20127

CRITICAL KEV

Cisco Catalyst SD-WAN - Auth Bypass

Title source: llm
STIX 2.1

Exploitation Summary

CVE-2026-20127 is actively exploited and listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added February 25, 2026. EIP tracks 13 public exploits from researchers including XiaomingX, zerozenxlabs, sfewer-r7, including a Metasploit module auxiliary/admin/networking/cisco_sdwan_auth_bypass.

AI-analyzed exploit summary The repository claims to provide an exploit for CVE-2026-20127 but lacks actual exploit code, instead directing users to an external download link. The README contains detailed usage instructions and technical claims but no functional code or technical analysis.

Description

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. 

Exploits (13)

github SUSPICIOUS 10 stars
by XiaomingX · pythonpoc
https://github.com/XiaomingX/data-cve-poc-py-v1/tree/main/2026/CVE-2026-20127

The repository claims to provide an exploit for CVE-2026-20127 but lacks actual exploit code, instead directing users to an external download link. The README contains detailed usage instructions and technical claims but no functional code or technical analysis.

Classification
Suspicious 90%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Theoretical
Target: Cisco SD-WAN (vManage)
No auth needed
Prerequisites: Python 3.9+ · Target exposed on port 443 · Outbound SSH/NETCONF allowed
devstral-2 · analyzed Mar 02, 2026 Full analysis →
nomisec WORKING POC 2 stars
by zerozenxlabs · remote
https://github.com/zerozenxlabs/CVE-2026-20127---Cisco-SD-WAN-Preauth-RCE

The repository contains a functional exploit for CVE-2026-20127, a pre-authentication RCE vulnerability in Cisco SD-WAN. The exploit leverages a hardcoded credential mechanism to bypass authentication and deploy a malicious WAR file, achieving remote code execution.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Cisco Catalyst SD-WAN Controller (vSmart) and Catalyst SD-WAN Manager (vManage)
No auth needed
Prerequisites: Network access to the target SD-WAN controller/manager · A malicious WAR file (e.g., 'cmd.war') for deployment
devstral-2 · analyzed Mar 04, 2026 Full analysis →
nomisec WORKING POC 1 stars
by sfewer-r7 · remote
https://github.com/sfewer-r7/CVE-2026-20127

This repository contains a functional exploit for CVE-2026-20127, targeting the Cisco Catalyst SD-WAN Controller authentication bypass vulnerability. The exploit leverages a forged CHALLENGE_ACK_ACK message to bypass certificate verification and gain unauthorized access.

Classification
Working Poc 100%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: Cisco Catalyst SD-WAN Controller (vSmart) version 20.15.3
No auth needed
Prerequisites: DTLS connection with a self-signed certificate · Target running vulnerable version of Cisco Catalyst SD-WAN Controller
devstral-2 · analyzed Mar 12, 2026 Full analysis →
nomisec WRITEUP 1 stars
by yonathanpy · poc
https://github.com/yonathanpy/CVE-2026-20127-Cisco-SD-WAN-Preauth-RCE

This repository provides a detailed technical analysis of CVE-2026-20127, a critical pre-authentication RCE vulnerability in Cisco SD-WAN. The README includes root cause analysis, exploitation mechanics, and real-world attack scenarios, but the Python exploit code is truncated and incomplete.

Classification
Writeup 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Theoretical
Target: Cisco Catalyst SD-WAN Controller (vSmart) and Cisco Catalyst SD-WAN Manager (vManage)
No auth needed
Prerequisites: Network access to vulnerable SD-WAN management interface · Exposed control-plane services
devstral-2 · analyzed Mar 07, 2026 Full analysis →
github WORKING POC
by XZ1r0 · pythonpoc
https://github.com/XZ1r0/cve-2026-poc-collection/tree/main/network/CVE-2026-20127

This repository contains a functional exploit for CVE-2026-20127, targeting a DTLS authentication bypass in vdaemon. The exploit leverages a forged CHALLENGE_ACK_ACK message to bypass authentication and inject SSH keys into the target system.

Classification
Working Poc 95%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: vdaemon (vEdge, vHub, vSmart, vBond, vManage)
No auth needed
Prerequisites: network access to the target · DTLS port accessibility
devstral-2 · analyzed May 21, 2026 Full analysis →
nomisec SCANNER
by gigachadusers · poc
https://github.com/gigachadusers/cve-2026-20127

The repository contains a C++-based network scanner that identifies potential Cisco SD-WAN / vManage services and checks for vulnerability to CVE-2026-20127 by sending crafted HTTP requests to specific endpoints. It does not include exploit code for achieving remote code execution or other offensive actions.

Classification
Scanner 90%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Cisco SD-WAN / vManage
No auth needed
Prerequisites: Network access to target IP range · Cisco SD-WAN / vManage service running on target
devstral-2 · analyzed Apr 16, 2026 Full analysis →
nomisec SCANNER
by abrahamsurf · poc
https://github.com/abrahamsurf/sdwan-scanner-CVE-2026-20127

This repository contains a passive fingerprinting tool designed to identify internet-facing Cisco SD-WAN (vManage / Viptela) instances by scanning common ports and analyzing HTTP/HTTPS responses, TLS certificates, and service banners. It does not exploit CVE-2026-20127 but helps detect potentially exposed management interfaces.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Cisco SD-WAN (vManage / Viptela)
No auth needed
Prerequisites: Python 3.7+ · Nmap installed · Python libraries: requests, python-nmap, ipaddress, asyncio, aiohttp
devstral-2 · analyzed Mar 08, 2026 Full analysis →
nomisec WORKING POC
by BugFor-Pings · poc
https://github.com/BugFor-Pings/CVE-2026-20127_EXP

This repository contains a functional exploit for CVE-2026-20127, an authentication bypass vulnerability in Cisco Catalyst SD-WAN. The exploit automates the process of retrieving a DCA key, logging in, uploading a WAR file, and verifying exploitation via two detection methods.

Classification
Working Poc 95%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: Cisco Catalyst SD-WAN
No auth needed
Prerequisites: target URL list · WAR file for payload delivery
devstral-2 · analyzed Mar 06, 2026 Full analysis →
nomisec WORKING POC
by leemuun · poc
https://github.com/leemuun/CVE-2026-20127

The repository contains a functional exploit for CVE-2026-20127, an authentication bypass vulnerability in Cisco Catalyst SD-WAN. The exploit leverages a directory traversal flaw to upload a malicious WAR file, enabling remote command execution via a deployed JSP webshell.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Cisco Catalyst SD-WAN (formerly SD-WAN vSmart/vManage)
No auth needed
Prerequisites: Python ≥ 3.6 · Access to the target's HTTP interface · A JSP webshell file
devstral-2 · analyzed Mar 05, 2026 Full analysis →
nomisec WRITEUP
by randeepajayasekara · poc
https://github.com/randeepajayasekara/CVE-2026-20127

This repository provides a detailed technical analysis of CVE-2026-20127, an authentication bypass vulnerability in Cisco SD-WAN (vSmart and vManage). It includes in-depth explanations of the vulnerability, exploitation steps, and patch analysis, but does not contain functional exploit code.

Classification
Writeup 100%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Theoretical
Target: Cisco SD-WAN Controller (vSmart) and SD-WAN Manager (vManage) versions 20.16.1 to 20.18.2.1
No auth needed
Prerequisites: Access to vulnerable Cisco SD-WAN instance · Understanding of SD-WAN control-plane peering mechanisms
devstral-2 · analyzed Mar 12, 2026 Full analysis →
nomisec WRITEUP
by bluefalconink · poc
https://github.com/bluefalconink/cisa-ed-26-03-tracker

This repository contains a detailed architectural documentation and compliance tracker for CISA ED 26-03, focusing on remediation steps for CVE-2026-20127 and CVE-2022-20775. It includes automated scripts to generate architecture diagrams and documentation but does not contain exploit code.

Classification
Writeup 95%
Attack Type
Other
Complexity
Moderate
Reliability
Theoretical
Target: Cisco SD-WAN (CVE-2026-20127 & CVE-2022-20775)
No auth needed
Prerequisites: Access to the compliance tracker application · Understanding of CISA ED 26-03 requirements
devstral-2 · analyzed Feb 27, 2026 Full analysis →
nomisec SUSPICIOUS
by Dimchuk · poc
https://github.com/Dimchuk/CVE-2026-20127-chain

The repository claims to exploit CVE-2026-20127 via an unauthenticated remote auth bypass but lacks actual exploit code, instead redirecting users to an external download link (tinyurl.com). The README is detailed but lacks technical depth and includes vague marketing language.

Classification
Suspicious 95%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Theoretical
Target: Cisco SD-WAN (vManage)
No auth needed
Prerequisites: Python 3.9+ · Target exposed on 443 · Outbound SSH/NETCONF allowed
devstral-2 · analyzed Feb 27, 2026 Full analysis →
metasploit WORKING POC
by sfewer-r7 · rubypoc
https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/admin/networking/cisco_sdwan_auth_bypass.rb

This Metasploit module exploits an authentication bypass vulnerability (CVE-2026-20127) in Cisco Catalyst SD-WAN Controller (vSmart) by manipulating the verify_status byte in CHALLENGE_ACK_ACK messages, allowing an unauthenticated attacker to gain trusted peer status and inject an SSH public key for persistent access.

Classification
Working Poc 100%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: Cisco Catalyst SD-WAN Controller (vSmart)
No auth needed
Prerequisites: Network access to the target's DTLS service (port 12346) · Self-signed certificate for DTLS handshake
devstral-2 · analyzed Apr 09, 2026 Full analysis →

Scores

CVSS v3 10.0
EPSS 0.5895
EPSS Percentile 98.3%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation active
Automatable yes
Technical Impact total

Details

CISA KEV 2026-02-25
VulnCheck KEV 2026-02-25
ENISA EUVD EUVD-2026-8675
CWE
CWE-287
Status published
Products (4)
cisco/catalyst_sd-wan_manager 20.12.6
cisco/catalyst_sd-wan_manager < 20.9.8.2
cisco/sd-wan_vsmart_controller 20.12.6
cisco/sd-wan_vsmart_controller < 20.9.8.2
Published Feb 25, 2026
KEV Added Feb 25, 2026
Tracked Since Feb 26, 2026