Cisco · Catalyst Sd-Wan Manager · CVE-2026-20182
**Name of the Vulnerable Software and Affected Versions**
Cisco Catalyst SD-WAN Controller (affected versions not specified)
Cisco Catalyst SD-WAN Manager (affected versions not specified)
Cisco Catalyst SD-WAN versions prior to 20.12.6.2
**Description**
A critical authentication bypass exists in the peering authentication mechanism of the control connection handshaking process. The flaw resides in the `vdaemon` service, where the system fails to properly validate incoming certificates and tokens if specific header options are altered. An unauthenticated remote attacker can exploit this by mimicking a legitimate network controller or vHub, sending crafted handshake packets or DTLS connections with self-signed certificates to induce a state-mismatch. This causes the validation subsystem to fall back to a permissive state, granting the attacker an administrative session token as a high-privileged internal user.
Successful exploitation provides access to NETCONF, allowing the attacker to manipulate global routing tables, inject malicious routing policies, modify network configurations for the SD-WAN fabric, and potentially escalate to root privileges. Real-world incidents involve a state-sponsored actor designated as UAT-8616, who has used this flaw to add SSH keys, deploy web shells, run XMRig miners, and steal AWS keys.
**Recommendations**
Update Cisco Catalyst SD-WAN to version 20.12.6.2 or newer.
Modify edge firewall rules to drop all traffic targeting controller management or synchronization ports unless it originates from pre-verified static IP addresses of known infrastructure peers.
Restrict all inbound external access to NETCONF endpoints globally.
Audit controller logs for unauthorized peering attachment sequences or abrupt configuration changes.
Perform a full user inventory via the CLI to identify unauthorized secondary administrative accounts.
Export global routing and security policy tables to perform a diff analysis against known-good backup baselines.