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UK Cyber Defence
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CVE-2026-20182

Cisco Catalyst SD-WAN Controller Authentication Bypass Vulnerability

KEVCRITICAL 10.0EPSS 91.5%

Does this matter?

Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 May 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.

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, 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.

CVSS 3.1
10.0 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS
91.52% probability · 100th percentile
CISA KEV
Listed 14 May 2026 · due 17 May 2026
Weakness
CWE-287
Affected
cisco/catalyst sd-wan manager · cisco/sd-wan vbond orchestrator · cisco/sd-wan vsmart controller
Source
psirt@cisco.com

CISA notes

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. CISA Mitigation Instructions: https://www.cisa.gov/news-events/directives/ed-26-03-mitigate-vulnerabilities-cisco-sd-wan-systems ; https://www.cisa.gov/news-events/directives/supplemental-direction-ed-26-03-hunt-and-hardening-guidance-cisco-sd-wan-systems ; https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa2-v69WY2SW ; https://nvd.nist.gov/vuln/detail/CVE-2026-20182

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.