CVE-2026-20127: Technical Deep-Dive (Auto Refreshed)

Generated on 2026-03-21T13:39:24.512Z. This file is automatically regenerated every 30 minutes by the CVE AI enrichment job using web sources (NVD, MITRE, CISA KEV, GitHub).

Executive Technical Summary

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 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. 

• Context preserved from previous revision: 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 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. 1. Use only isolated environments and assets you own or are explicitly authorized to test.

Technical Details

• CVE: CVE-2026-20127
• KEV date added: 2026-02-25
• KEV due date: 2026-02-27
• NVD published: 2026-02-25
• NVD modified: 2026-02-26
• MITRE modified: 2026-02-26
• CVSS base score: 10
• CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
• CVSS exploitability score: 3.9
• CVSS impact score: 6
• Attack vector: Network
• Attack complexity: Low
• Privileges required: None
• User interaction: None
• Scope: Changed
• Confidentiality impact: High
• Integrity impact: High
• Availability impact: High

Versions and Products Impacted

• cisco / catalyst sd-wan manager (versions: < 20.9.8.2)
• cisco / catalyst sd-wan manager (versions: >= 20.11, < 20.12.5.3)
• cisco / catalyst sd-wan manager (versions: >= 20.13, < 20.15.4.2)
• cisco / catalyst sd-wan manager (versions: >= 20.16, < 20.18.2.1)
• cisco / catalyst sd-wan manager (versions: 20.12.6)
• cisco / sd-wan vsmart controller (versions: < 20.9.8.2)
• cisco / sd-wan vsmart controller (versions: >= 20.11, < 20.12.5.3)
• cisco / sd-wan vsmart controller (versions: >= 20.13, < 20.15.4.2)
• cisco / sd-wan vsmart controller (versions: >= 20.16, < 20.18.2.1)
• cisco / sd-wan vsmart controller (versions: 20.12.6)
• Cisco / Cisco Catalyst SD-WAN Manager (versions: 20.1.12, 19.2.1, 18.4.4, 18.4.5, 20.1.1.1, 20.1.1, 19.3.0, 19.2.2, 19.2.099, 18.3.6)

Weakness Classification

• CWE-287

Repositories for Lab Validation (Public Examples)

• nomi-sec/PoC-in-GitHub | stars: 7586 | updated: 2026-03-21 | https://github.com/nomi-sec/PoC-in-GitHub
  Notes: 📡 PoC auto collect from GitHub. ⚠️ Be careful Malware.
• GhostTroops/TOP | stars: 720 | updated: 2026-03-21 | https://github.com/GhostTroops/TOP
  Notes: TOP All bugbounty pentesting CVE-2023- POC Exp RCE example payload Things

People and Organizations Mentioned

• cisco
• Catalyst SD-WAN Controller and Manager
• nomi-sec
• GhostTroops

Practical Defensive Validation (Authorized Only)

1. Use only isolated environments and systems you own or are explicitly authorized to test.
2. Snapshot infrastructure before validation and preserve baseline logs (EDR, SIEM, OS, app).
3. Inventory cisco / catalyst sd-wan manager (versions: < 20.9.8.2) assets and confirm exact vulnerable versions with automated checks.
4. Patch in staged environments and validate closure with scanners + service health checks.
5. Map detections to MITRE ATT&CK tactics relevant to your environment and tune alert quality.

References

• NVD record: https://nvd.nist.gov/vuln/detail/CVE-2026-20127
• MITRE CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20127
• CISA KEV Catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• CISA KEV JSON feed: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json
• KEV notes: 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-rpa-EHchtZk ; https://nvd.nist.gov/vuln/detail/CVE-2026-20127
• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa-EHchtZk
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20127
• Repository example: https://github.com/nomi-sec/PoC-in-GitHub
• Repository example: https://github.com/GhostTroops/TOP

This content is for defensive security training and authorized validation only.