Cisco SD-WAN Zero-Day: 3-Year APT Campaign Analysis

Originally published on satyamrastogi.com Cisco SD-WAN zero-day CVE-2026-20127 exploited for 3 years by sophisticated APT group with minimal forensic evidence. Critical infrastructure targeting via network edge compromise. Executive Summary A previously unknown APT group successfully exploited CVE-2026-20127 , a maximum-severity zero-day vulnerability in Cisco SD-WAN infrastructure, for approximately three years before detection. The threat actor demonstrated advanced operational security by leaving minimal forensic evidence while maintaining persistent access to critical network infrastructure. This campaign represents a sophisticated supply chain attack vector targeting enterprise network perimeters through compromised SD-WAN management interfaces. Attack Vector Analysis The CVE-2026-20127 vulnerability provides attackers with a direct pathway into enterprise network infrastructure through compromised SD-WAN management interfaces. From a red team perspective, this represents an ideal