Patchfirst
CVE-2026-20182 KEVPublic exploit Critical · 10.0 EPSS 91.8%

Cisco Catalyst SD-WAN Controller Authentication Bypass Vulnerability

Cisco · Catalyst SD-WAN

Summary

A flaw in the peering authentication mechanism of Cisco Catalyst SD-WAN Controller (formerly vSmart), Cisco Catalyst SD-WAN Manager (formerly vManage), and Cisco Catalyst SD-WAN Validator (formerly vBond) causes improper authentication during control connection handshaking. An unauthenticated remote attacker who sends crafted requests to an affected system can bypass authentication and log in as an internal, high-privileged, non-root account, then use NETCONF to manipulate the SD-WAN fabric's network configuration.

Official description · NVD

May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and fixed after the was disclosed in February 2026. This new advisory is for a new vulnerability in the control connection handshaking. The section of this advisory includes Show Control Connections guidance to help with system checks.  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 the 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.

Breakdown
83.9 / 100
Exploited
Yes, in CISA KEV
Reports
4
Tactics
1/15

How an attack unfolds

Based on mappings. Select a step to see the evidence.
  1. How attackers get in

First seen exploited the day it was disclosed. Public exploit code (Metasploit) was available 7 days before disclosure.

  1. First dated threat reportblog.talosintelligence.com7 yrs before
  2. Public exploit codeMetasploit7 days before
  3. DisclosedFirst seen exploitedVulnCheck KEV evidenceAdded to CISA KEVEU database agreesday 0

CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.

techniques

1 , grouped by in kill-chain order, 1 cited passage 1

Initial AccessTA0001

Exploit Public-Facing Application T1190 Medium
AI mapping from the description · how it is exploited

unauthenticated remote exploit of public-facing service

could allow an unauthenticated, remote attacker to bypass authentication
From the official description (NVD) Original (opens in a new tab) ↗

Detection

0 rules for this CVE · 149 general rules for its techniques

Rules for this CVE

0 that reference CVE-2026-20182 directly.

CVE-specific rules are not available in this build. Search SigmaHQ ↗

General rules for this CVE’s techniques

These detect the technique in general, not this specific vulnerability.

Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.

What security researchers reported

Named in 4 threat reports
4 reportsCisco Talos4Apr 2019 – Apr 2024

Reports are matched by finding the exact id CVE-2026-20182 in their text; nobody has reviewed the match. One passage is shown per report, at most 320 characters, linked to the original.

Cisco Talos8 Dec 2022

Breaking the silence

Cisco Talos is tracking the active exploitation of CVE-2026-20182, an authentication bypass vulnerability in Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, and Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage.

Original (opens in a new tab) ↗

Also mentioned in 50 community threat pulses (AlienVault OTX)

Weaker evidence

Pulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.

References

3 links, grouped by NVD tag
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