# CVE-2026-20127: Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass Vulnerability

- Exploited (CISA KEV): yes, added 2026-02-25
- Published: 2026-02-25
- CVSS: 10 CRITICAL (v3.1)
- EPSS: 89.3% (100th percentile)
- CWE: CWE-287

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. 

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | No public claim | — | — |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | No public claim | — | — |
| Fastly | Before feed history | — | — |
| F5 | No public claim | — | — |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

## Social

2 posts seen since 2026-11-02.

- bluesky 2026-11-02: Volt Typhoon hit endpoint management platforms, network management systems and SD-WAN orchestrators across 4 zero-day campaigns. Hundreds of victims. Sessions averaged 4 hours, then every artifact was removed. Ask your IT provider whether CVE-2026-20127 applies to anything in yo… (https://bsky.app/profile/theautomate.bsky.social/post/3mzecphv2fd2t)
- x 2026-11-02: Volt Typhoon ran 4 zero-day campaigns through a covert network targeting endpoint management platforms and SD-WAN orchestrators. Hundreds of victims. Sessions averaged 4 hours, then every artifact was cleaned up. Ask your IT provider about CVE-2026-20127 and CVE-2026-16812. (https://x.com/theautomate_io/status/2117374396675321923)

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

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