CVEs / CVE-2026-20127
CVE-2026-20127: Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass Vulnerability
- Known exploited in the CISA KEV catalog since 25 Feb 2026
- critical 10 CVSS 3.1 (NVD)
- EPSS 89.2% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
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.
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Cisco Cisco Catalyst SD-WAN Manager | 20.1.12 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 19.2.1 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.4.4 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.4.5 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 20.1.1.1 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 20.1.1 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 19.3.0 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 19.2.2 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 19.2.099 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.3.6 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.3.7 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 19.2.0 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.3.8 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 19.0.0 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 19.1.0 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.4.302 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.4.303 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 19.2.097 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 19.2.098 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 17.2.10 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.3.6.1 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 19.0.1a | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.2.0 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.4.3 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.4.1 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 17.2.8 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.3.3.1 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.4.0 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 18.3.1 | — |
| Cisco Cisco Catalyst SD-WAN Manager | 17.2.6 | — |
Exploitation
| In CISA KEV since | 25 Feb 2026 |
|---|---|
| Due date for US federal agencies | 27 Feb 2026 |
| Used in ransomware campaigns | Unknown |
| 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. |
Severity
| CVSS 3.1 | 10 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HScored by NVD |
|---|---|
| Weakness | CWE-287 |
References
- CVE-2026-20127 on NVD
- CVE-2026-20127 in the CISA KEV catalog
- https://www.cisa.gov/news-events/directives/ed-26-03-mitigate-vulnerabilities-cisco-sd-wan-systems (cited by CISA)
- https://www.cisa.gov/news-events/directives/supplemental-direction-ed-26-03-hunt-and-hardening-guidance-cisco-sd-wan-systems (cited by CISA)
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa-EHchtZk (cited by CISA)
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa-EHchtZk Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20127 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.