CVE-2026-20127: Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass Vulnerability

In short

Cisco Catalyst SD-WAN Controller and Manager has a weakness classified as improper authentication (CWE-287). CISA added it to its Known Exploited Vulnerabilities catalog on 2026-02-25. NVD lists CVSS 3.1 at 10 CRITICAL.

What it 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.” — CISA KEV, retrieved 2026-11-01

“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 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. ” — NVD, retrieved 2026-11-01

Who is affected

Cisco Catalyst SD-WAN Controller and Manager. NVD lists the following versions as affected:

• Cisco Catalyst SD-WAN Manager: before 20.9.8.2
• Cisco Catalyst SD-WAN Manager: from 20.11 inclusive, before 20.12.5.3
• Cisco Catalyst SD-WAN Manager: from 20.13 inclusive, before 20.15.4.2
• Cisco Catalyst SD-WAN Manager: from 20.16 inclusive, before 20.18.2.1
• Cisco Catalyst SD-WAN Manager: version 20.12.6
• Cisco SD-WAN Vbond Orchestrator: before 20.9.8.2
• Cisco SD-WAN Vbond Orchestrator: from 20.11 inclusive, before 20.12.5.3
• Cisco SD-WAN Vbond Orchestrator: from 20.13 inclusive, before 20.15.4.2
• Cisco SD-WAN Vbond Orchestrator: from 20.16 inclusive, before 20.18.2.1
• Cisco SD-WAN Vbond Orchestrator: version 20.12.6
• Cisco SD-WAN Vsmart Controller: before 20.9.8.2
• Cisco SD-WAN Vsmart Controller: from 20.11 inclusive, before 20.12.5.3
• Cisco SD-WAN Vsmart Controller: from 20.13 inclusive, before 20.15.4.2
• Cisco SD-WAN Vsmart Controller: from 20.16 inclusive, before 20.18.2.1
• Cisco SD-WAN Vsmart Controller: version 20.12.6

Exploitation status

CISA KEV added: 2026-02-25. Known ransomware campaign use: Not reported by CISA. Due date CISA set for US federal civilian agencies: 2026-02-27.

Scores

NVD CVSS 3.1: 10 CRITICAL; vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H; source [email protected].

EPSS by FIRST: 89.29%; percentile 99.78; score date 2026-10-31. EPSS estimates the probability of exploitation in the next 30 days.

CWE: CWE-287.

Timeline

CISA required action

“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.” — CISA KEV

What to do

• Confirm whether you run Cisco Catalyst SD-WAN Controller and Manager and which version.
• Apply the vendor update or mitigation in the advisory.
• Follow CISA’s required action.
• Review the vendor guidance on signs of compromise.
• Track the fix through completion.

References

• Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa-EHchtZk
• NVD detail
• CVE.org record
• CISA KEV catalog

Sources and dates

CISA Known Exploited Vulnerabilities Catalog, version 2026.10.30; retrieved 2026-11-01. CISA KEV data: CC0 1.0. No endorsement by CISA.

NVD retrieved: 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.

EPSS scores by FIRST; score date 2026-10-31.