CVE-2026-20127

What the flaw is

Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, and Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, contain an authentication bypass vulnerability 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.

Description as published by CISA. We have not independently reproduced it.

What CISA requires

Please adhere to CISA’s guidelines to assess exposure and mitigate risks associated with Cisco SD-WAN devices as outlines 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.

This deadline is binding on US federal civilian agencies under BOD 22-01. It is not a legal deadline for anyone else, but it is a useful urgency signal — CISA sets it by how actively the flaw is being used, not by CVSS.

Public exploit code

We hold no public exploit references for this CVE. That means our dataset has none — it is not evidence that no exploit exists. CISA has confirmed this vulnerability is being exploited in the wild regardless.

Vendor advisories

• www.cisa.gov/news-events/directives/ed-26-03-mitigate-vulnerabilities-cisco-sd
• www.cisa.gov/news-events/directives/supplemental-direction-ed-26-03-hunt-and-h
• sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa
• nvd.nist.gov/vuln/detail/CVE-2026-20127

Primary sources

• NVD entry — CVSS score, CPE list and references
• CISA KEV catalog — the source for this page
• CVE Record at cve.org