Cisco SD-WAN Zero-Day Exploited by Threat Actor Since 2023

A cyber threat actor has been exploiting a zero-day vulnerability (CVE-2026-20127) in Cisco Catalyst SD-WAN Controller since 2023. This vulnerability allows unauthenticated remote attackers to bypass authentication and gain administrative privileges, potentially leading to long-term persistence in affected systems. Cisco and the Australian Cyber Security Centre have reported the ongoing exploitation of this vulnerability.