Cisco Secure Firewall Vulnerability Exposes Networks to Authentication Bypass Attacks

**Executive Summary:** Cisco disclosed a critical authentication-bypass vulnerability (CVE-2026-20079, CVSS 10.0) in on-premises Secure Firewall Management Centre (FMC) that allows unauthenticated remote attackers to execute scripts and gain root access via specially crafted HTTP requests; there are no mitigations other than upgrading to a patched release, and Cisco reports no observed in-the-wild exploitation as of March 2026.