Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel — exploitable from the network with no login

What it is

Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management contain an authentication Bypass using an alternate path or channel vulnerability that could allow an unauthenticated, remote attacker to bypass authentication and execute script files on an affected device to obtain root access to the underlying operating system.

Why it matters

• CISA added it to the Known Exploited Vulnerabilities catalogue on September 9, 2026 — observed exploitation, on the record.
• EPSS puts the chance of exploitation in the next 30 days at 74.7% — the top 0.5% of all scored CVEs.
• CVSS 10.0 (critical), and it is reachable over the network, needs no credentials, needs no user interaction.

What to do

• Patch it. CISA's due date for federal agencies is September 12, 2026, which is as good a deadline as any for everyone else.
• Check Cisco's advisory for affected versions: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-onprem-fmc-authbypass-5JPp45V2

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Drafted from CVE-2026-20079 — CISA KEV, NVD, FIRST EPSS. Check before publishing.