Summary
| Parameter | Value |
|---|---|
| CVE ID | CVE-2026-20127 |
| Alert Source | CISA KEV - Active Exploitation |
| CVE Publication Year | 2026 |
| Date Published | 2026-02-25 |
| Vendor | Cisco |
| Product | Catalyst SD-WAN Controller and Manager |
| CVSS Score | 10.0 (critical) |
| EPSS Score | No data |
| CISA KEV | Yes - confirmed active exploitation |
| Ransomware | Not confirmed |
| Remediation Deadline | 2026-02-27 |
Vulnerability Description
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.
Required Actions
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.
Who Is Affected?
This vulnerability affects Catalyst SD-WAN Controller and Manager by Cisco. Check if your organization uses this software and requires updates.
Sources
Need help securing your systems? nFlo team offers vulnerability management and 24/7 SOC services. Contact us.
How can nFlo help?
If your organization uses products affected by this vulnerability, contact us. We can help with:
- Verifying whether your systems are at risk
- Implementing patches and risk mitigation
- Monitoring for exploitation attempts in your environment
Useful resources:
Related topics
See also:
Frequently asked questions
What is CVE-2026-20127?
CVE-2026-20127 is a vulnerability discovered in Cisco's Catalyst SD-WAN Controller and Manager. 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, rem. The severity is rated as critical (CVSS: 10).
Who is affected by CVE-2026-20127?
This vulnerability affects users of Cisco's Catalyst SD-WAN Controller and Manager. Any organization using this software should immediately verify whether their systems require patching or mitigation measures.
How can I protect against CVE-2026-20127?
Apply the security patches provided by Cisco or implement the recommended mitigations. CISA has set a remediation deadline of 2026-02-27. If patches are unavailable, consider disabling the vulnerable component.
Why is CVE-2026-20127 classified as critical?
This vulnerability received a CVSS score of 10, classifying it as critical. This means it can be easily exploited by attackers and may lead to severe consequences such as system takeover, data theft, or service disruption.
Is CVE-2026-20127 actively exploited in the wild?
Yes, CISA has added this vulnerability to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in real-world attacks. Ransomware usage has not been confirmed yet, but the risk remains high.
