Week in review: Linux rootkit deployed on F5 BIG-IP APM devices, Cisco FMC bugs exploited
Weekly roundup: Cisco FMC and N-able N-central zero-days exploited in the wild, MikroTik RouterOS hijacks, Microsoft Patch Tuesday ships two exploited zero-days.
State-sponsored and financially-motivated attackers are actively exploiting CVE-2026-20079, a critical authentication bypass in Cisco Secure Firewall Management Center (FMC), alongside CVE-2026-20316. N-able issued an emergency hotfix for CVE-2026-86218, a critical pre-auth RCE in the N-central RMM platform exploited in the wild. CERT Polska disclosed six RouterOS vulnerabilities being chained to hijack internet-exposed MikroTik devices. Microsoft's September 2026 Patch Tuesday shipped a record patch count including two zero-days, while roughly 67,000 Trezor customers faced phishing after a shipping-partner breach and researchers privately disclosed a zero-click WeChat worm to Tencent.
Hackers Exploit Critical Cisco Firewall Flaw to Gain Root Access and Deploy Malware
State-sponsored and ransomware actors actively exploit critical Cisco FMC flaws CVE-2026-20079 (CVSS 10.0) and CVE-2026-20316 to gain root access and deploy ransomware.
Cisco Talos confirmed in-the-wild exploitation of CVE-2026-20079 (CVSS 10.0, unauthenticated authentication bypass enabling root command execution) and CVE-2026-20316 (CVSS 5.3, hard-coded static credentials) in Cisco Secure Firewall Management Center. Three activity clusters were identified: UAT-12197 dropping a JSP web shell and credential harvester; UAT-11823, assessed as Sandworm, deploying a Cyclops Blink variant; and UAT-11988, a Qilin ransomware affiliate chaining the flaws before deploying ransomware. CISA added both CVEs to the KEV catalog with a September 12 remediation deadline for federal agencies.
Active exploitation of Cisco Secure Firewall Management Center vulnerabilities
Cisco Talos reports in-the-wild exploitation of critical FMC flaw CVE-2026-20079 by three clusters including a Sandworm-linked APT and Qilin ransomware affiliates.
Cisco Talos is tracking active exploitation of CVE-2026-20079 (CVSS 10.0), an authentication bypass in Cisco Secure Firewall Management Center that lets unauthenticated remote attackers execute scripts and obtain root access, and CVE-2026-20316 (CVSS 5.3), which permits low-privileged logins and can be chained for privilege escalation. Talos identified three post-compromise clusters: UAT-12197 deploying JSP web shells and a JAR command executor for credential theft; UAT-11823, an APT overlapping with Sandworm, deploying a Netcat reverse shell and Cyclops Blink malware; and UAT-11988, assessed as a ransomware operator with TTPs consistent with Qilin affiliates. Hotfixes are available, with a comprehensive hardening release due the week of September 14, 2026.