Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel Vulnerability (CVE-2026-20079)
Severity: critical · Patch status: unknown · Since 2026-09-09 · CVE-2026-20079
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. CISA added CVE-2026-20079 to its Known Exploited Vulnerabilities catalog on Sep 9, 2026, which means attackers are exploiting it in the wild.
What to do
- Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
- US federal agencies must remediate by Sep 12, 2026 (BOD 22-01); treat that as the outer limit.
Sources
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