Executive summary
Public evidence documents CVE-2026-20127. This report does not assess any organization.
Technical analysis
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.
Evidence and sources
Public evidence for CVE-2026-20127 with preserved provenance.
CVE-2026-20127 Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass Vulnerability 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.
IOCs
No public IOC is available.
CVEs and affected products
Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass Vulnerability
ATT&CK mapping
No ATT&CK mapping is available.
Detection content
Sigma rules, YARA rules, Splunk SPL, and KQL detection logic.
Threat hunting
Hypothesis-driven hunt procedures and telemetry checklist.
Remediation
Containment actions, patching notes, and credential steps.
Historical relationships
No published historical relationship is available.
Timeline and change history
Confidence and caveats
1.0
⚠️ Public CTI only; no organizational exposure is asserted.
⚠️ CVSS and EPSS metadata were not present in the retrieved evidence payload.