BREAKING: Cisco SD-WAN Manager admin API open without a login (CVE-2026-76504)

How to fix CVE-2026-76504: upgrade Cisco Catalyst SD-WAN Manager to 20.9.10.1 / 20.12.8.2 / 20.15.6.1 / 20.18.4.1 / 26.1.2.1 / 26.2.1. Same-day Cisco PSIRT advisory with active exploitation; unauth admin API via URI-encoding bypass.