Cisco Security Advisories guidance
Vendor revision: Oct 28, 2026Cisco has released software updates that address this vulnerability.
Overview
What is CVE-2026-20127?
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.
Source: NVD
CISA says: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 catalog due date Feb 27, 2026
Official advisory
Configuration and update guidance
Cisco Security Advisories · Updated Oct 28, 2026
Affected products and configuration
This vulnerability affects Cisco Catalyst SD-WAN Controller, Cisco Catalyst SD-WAN Manager, and Cisco Catalyst SD-WAN Validator, regardless of device configuration.
This vulnerability affects the following deployment types:
On-Prem Deployment
Cisco Hosted SD-WAN Cloud
Cisco Hosted SD-WAN Cloud - Cisco Managed
Cisco Hosted SD-WAN Cloud - FedRAMP Environment
For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.
Workarounds and temporary mitigations
There are no workarounds that address this vulnerability. However, as a mitigation, customers may use the following guidance to temporarily mitigate the impact of this vulnerability while they are planning to upgrade to a first fixed release.
Action Owner | On-Prem Deployment |
|---|---|
Customer | Follow the guidelines in the Firewall Ports for Cisco Catalyst SD-WAN Deployments section of the Cisco Catalyst SD-WAN Getting Started Guide. Customers who host their own Cisco Catalyst SD-WAN deployment in their own data centers must secure intra-controller connectivity. Cisco recommends adding the access control lists (ACLs), security group rules, and/or firewall rules to restrict the traffic to port 22 and port 830 to allow only known controller IPs and other known IPs. Customers also must configure their mitigation ACLs to allow IP traffic from only specified hosts or devices that require access to the Cisco Catalyst SD-WAN Control Components. |
Action Owner | Cisco Hosted SD-WAN Cloud |
Customer | These guardrails are in place for Cisco Hosted SD-WAN Cloud. |
Action Owner | Cisco Hosted SD-WAN Cloud - FedRAMP Environment |
Customer | These guardrails are in place for Cisco Hosted SD-WAN Cloud - FedRAMP Environment. |
Action Owner | Cisco Hosted SD-WAN Cloud - Cisco Managed |
Customer and Cisco | These guardrails are in place for Cisco Hosted SD-WAN Cloud - Cisco Managed. |
While this mitigation has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations.
Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.
Fixed software
Cisco considers any workarounds and mitigations (if applicable) to be temporary solutions until an upgrade to a fixed software release is available. To fully remediate these vulnerabilities and avoid future exposure as described in this advisory, Cisco strongly recommends that customers upgrade to the fixed software indicated in this advisory.
Fixed Releases
In the following table, the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerability that is described in this advisory and the first release that includes the fix for this vulnerability. Customers are advised to upgrade to an appropriate fixed software release as indicated in this section.
Cisco Catalyst SD-WAN Release | First Fixed Release |
|---|---|
Earlier than 20.91 | Migrate to a fixed release. |
20.9 | 20.9.8.2 |
20.111 | 20.12.6.1 |
20.12 | 20.12.5.3 20.12.6.1 |
20.131 | 20.15.4.2 |
20.141 | 20.15.4.2 |
20.15 | 20.15.4.2 |
20.161 | 20.18.2.1 |
20.18 | 20.18.2.1 |
1. These releases have reached End of Software Maintenance. Cisco strongly encourages customers to upgrade to a supported release.
The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.
Additional Information
To check component and software release compatibility, see the SD-WAN Controller Component Compatibility Matrix.
For help planning an upgrade, see the Cisco Catalyst SD-WAN Upgrade Matrix.
For additional remediation assistance, see Remediate Catalyst SD-WAN Security Advisory - February 2026
Exploitation status
The Cisco PSIRT is aware of limited exploitation of this vulnerability. Cisco continues to strongly recommend that customers upgrade to a fixed software release to remediate this vulnerability.
Customers can review additional information in the following Talos Intelligence Blog post: https://blog.talosintelligence.com/uat-11473-keydrift/.