CISA Warns of Cisco Secure Firewall Management Center 0-Day Exploited in Ransomware Attacks

An urgent warning highlights a critical zero-day in Cisco products, now added to the CISA Known Exploited Vulnerabilities Catalog after active exploitation in ransomware campaigns.

Network defenders and security administrators are urged to take immediate action.

The rapid exploitation of this vulnerability by financially motivated threat actors highlights the severe risk it poses to enterprise networks globally.

Cisco Firewall 0-Day Exploited

Tracked as CVE-2026-20131, the security flaw impacts both Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management.

The core issue resides within the web-based management interface of these applications. Specifically, the vulnerability is classified as a deserialization of untrusted data flaw, documented under CWE-502.

Deserialization vulnerabilities occur when an application…