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…
- Severity
- 10.0 / 10
- Critical · CVSS 3.1
- Exploit chance (EPSS)
- 89.29%
- Chance of exploitation in the next 30 days. Higher than 99.78% of scored vulnerabilities.
- Known exploited
- Yes
- In CISA's catalog since Feb 25, 2026
- Fix
- None yet
- No fixed version published
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.
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
Severity breakdown
CVSS 3.1 10.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-287: 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 to prevent it
- Architecture and Design: Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
CWE-287: 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 to prevent it
- Architecture and Design: Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
References
Advisories
Other links
Timeline
- Added to CISA's Known Exploited Vulnerabilities catalog
- Published
- Remediation due for U.S. federal agencies
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-f9x3-7vq9-cph6 Laravel TokenGuard authentication bypass through non-string API credentials | Critical | Same weakness, CWE-287 |
| GHSA-r4xp-prcw-77qf better-auth: OAuth Proxy lets an attacker sign in as another user | Critical | Same weakness, CWE-287 |
| GHSA-965c-763c-88jm better-auth: OAuth state can be used as a Magic Link to sign in as another user | Critical | Same weakness, CWE-287 |
| GO-2026-6773 Nginx UI: Casdoor SSO callback uses a constant `state` parameter (login CSRF) | High | Same weakness, CWE-287 |
| GO-2026-6786 Nginx UI: TOTP / passkey enrolment requires no re-authentication, enabling persistent account takeover | High | Same weakness, CWE-287 |
| GHSA-xv7q-fvmc-jx96 Vikunja: OIDC email-fallback account linking ignores email_verified, enabling local-account takeover | High | Same weakness, CWE-287 |
| GHSA-68w4-83fh-f2w8 pyload-ng: getUserData/get_userdata exposed at Perms.ANY allow any authenticated account to brute-force the administrator password | High | Same weakness, CWE-287 |
| GHSA-r44w-v6gf-x3p6 pyLoad has an authentication bypass in API key validation (check_apikey cache) | High | Same weakness, CWE-287 |
MergeHarbor checks every repository's dependencies against this database, ranks what matters by exploitability and reachability, routes it to the owning team and opens the fix pull request.
Check your repos with MergeHarbor