Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass
CVE-2026-20127 is a critical-severity improper authentication vulnerability in Cisco Catalyst SD-WAN Manager from Cisco, with a CVSS 3.1 base score of 10.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Cisco Catalyst SD-WAN Manager versions: 20.1.12; 19.2.1; 18.4.4, and others listed below. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on February 25, 2026, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Catalyst Sd-wan Manager to 20.9.8.2 or 20.12.5.3 or 20.15.4.2 or 20.18.2.1, whichever matches your release line, or a later version.
- Update Sd-wan Vbond Orchestrator to 20.9.8.2 or 20.12.5.3 or 20.15.4.2 or 20.18.2.1, whichever matches your release line, or a later version.
- Update Sd-wan Vsmart Controller to 20.9.8.2 or 20.12.5.3 or 20.15.4.2 or 20.18.2.1, whichever matches your release line, or a later version.
- CISA's 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.
- Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco Catalyst SD-WAN Manager | 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; and 32 more ranges | Not stated |
| Cisco | Catalyst Sd-wan Manager | before 20.9.8.2; 20.11 up to, but not including, 20.12.5.3; 20.13 up to, but not including, 20.15.4.2; 20.16 up to, but not including, 20.18.2.1; 20.12.6 | 20.9.8.2, 20.12.5.3, 20.15.4.2, 20.18.2.1 |
| Cisco | Sd-wan Vbond Orchestrator | before 20.9.8.2; 20.11 up to, but not including, 20.12.5.3; 20.13 up to, but not including, 20.15.4.2; 20.16 up to, but not including, 20.18.2.1; 20.12.6 | 20.9.8.2, 20.12.5.3, 20.15.4.2, 20.18.2.1 |
| Cisco | Sd-wan Vsmart Controller | before 20.9.8.2; 20.11 up to, but not including, 20.12.5.3; 20.13 up to, but not including, 20.15.4.2; 20.16 up to, but not including, 20.18.2.1; 20.12.6 | 20.9.8.2, 20.12.5.3, 20.15.4.2, 20.18.2.1 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 10.0 | Critical | CNA (cisco.com) |
| CVSS 3.1 | 10.0 | Critical | NVD |
Official description
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: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20127US Government Resource
Other vulnerabilities in Cisco Catalyst SD-WAN Manager
- 9.8 Critical severity
- 7.7 High severity
- 8.8 High severity
- 9.1 Critical severity
- 9.9 Critical severity
- 9.9 Critical severity
Recent Improper Authentication vulnerabilities
- 9.8 Critical severity
- 7.5 High severity
- 9.1 Critical severity
- 8.1 High severity
- 9.4 Critical severity
- 10.0 Critical severity
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