🔴 Critical | Source: CISA Known Exploited Vulnerabilities
Cisco Secure Firewall Management Center (FMC) contains a hard-coded password that allows an unauthenticated remote attacker to log in using a low-privileged account. This type of vulnerability is particularly dangerous because it requires no credentials to exploit and is trivial to abuse once the password is publicly known. CISA has confirmed active exploitation in the wild, with remediation required by 1 August 2026.
Security Architect’s Take: Patch affected Cisco FMC instances immediately and verify that management interfaces are not exposed to the internet or untrusted networks — place FMC behind a dedicated management VPC or bastion with strict network ACLs. Audit access logs for any unexpected low-privileged account activity as a potential indicator of prior compromise.
Original advisory: CVE-2026-20316: Cisco Secure Firewall Management Center (FMC)