Zero-Day Exploitation of Vulnerability (CVE-2026-20245) in Cisco Catalyst SD-WAN Manager

Written by: Chester Sng, Pete Boonyakarn, Logeswaran Nadarajan, Lukasz Lamparski Introduction In early 2026, Mandiant identified a threat actor targeting SD-WAN infrastructure at a service provider. After gaining initial access, the threat actor exploited a zero-day vulnerability ( CVE-2026-20245 ) in Cisco Catalyst SD-WAN to escalate privileges from a compromised administrative account to root-level access. The vulnerability stems from the device’s file upload feature lacking the ability to properly filter malicious data.