CVE-2026-20182

Published May 14, 2026

Last updated 5 days ago

Overview

AI description

Automated description summarized from trusted sources.

CVE-2026-20182 is an authentication bypass vulnerability affecting Cisco Catalyst SD-WAN Controller (formerly vSmart) and Cisco Catalyst SD-WAN Manager (formerly vManage). The flaw resides in the peering authentication mechanism during the control connection handshaking process, which does not function correctly. This allows an unauthenticated, remote attacker to bypass authentication by sending crafted requests to the affected system. A successful exploit enables the attacker to log in to an affected Cisco Catalyst SD-WAN Controller as a high-privileged, non-root user account. From this position, the attacker can access NETCONF, which then allows them to manipulate the network configuration for the entire SD-WAN fabric. This vulnerability has been added to CISA's Known Exploited Vulnerabilities Catalog.

Description: 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, 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 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.
Source: psirt@cisco.com
NVD status: Analyzed
Products: catalyst_sd-wan_manager, sd-wan_vsmart_controller

Risk scores

CVSS 3.1

Type: Secondary
Base score: 10
Impact score: 6
Exploitability score: 3.9
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Severity: CRITICAL

Known exploits

Data from CISA

Vulnerability name: Cisco Catalyst SD-WAN Controller Authentication Bypass Vulnerability
Exploit added on: May 14, 2026
Exploit action due: May 17, 2026
Required action: Please adhere to CISA’s guidelines to assess exposure and mitigate risks associated with Cisco SD-WAN devices as outlined in CISA’s Emergency Directive 26-03 (URL listed below in Notes) and CISA’s Hunt & Hardening Guidance for Cisco SD-WAN Devices (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.

Weaknesses

psirt@cisco.com: CWE-287

Hype score: Not currently trending

Configurations

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]

References

Sources include official advisories and independent security research.