VERY IMPORTANT

Cisco Talos is tracking active exploitation of two vulnerabilities in Secure Firewall Management Center (FMC) Software. CVE-2026-20079 is a critical authentication bypass vulnerability allowing remote attackers to execute scripts and obtain root access. CVE-2026-20316 enables remote login using low-privileged accounts and can be chained with other vulnerabilities for privilege escalation. Three distinct threat actor clusters have been identified conducting post-compromise activities: UAT-12197 deployed web shells and credential theft tools; UAT-11823, overlapping with Russian APT Sandworm, deployed Cyclops Blink malware and established reverse shells; UAT-11988, a Qilin ransomware operator, conducted extensive reconnaissance, credential harvesting, and deployed ransomware after establishing persistent network access through tunneling tools. Customers are strongly advised to apply available hotfixes immediately.