ACTIVELY EXPLOITED
CVE-2026-20131: Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data Vulnerability
| Vendor | Cisco |
|---|---|
| Product | Secure Firewall Management Center (FMC) |
| Actively exploited | Yes |
| Added to CISA KEV | 19 Mar 2026 |
| CISA federal deadline | 22 Mar 2026 |
| Ransomware use | Known |
| Weakness (CWE) | CWE-502 |
Required action (CISA's text)
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Description (NVD)
Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management contain a deserialization of untrusted data vulnerability in the web-based management interface that could allow an unauthenticated, remote attacker to execute arbitrary Java code as root on an affected device.
SOURCES
Other Cisco flaws
- CVE-2026-20320: Cisco BroadWorks Improper Restriction of XML External Entity Reference Vulnerability
- CVE-2026-76418: Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability
- CVE-2026-76519: Cisco Secure Email Gateway Relative Path Traversal Vulnerability
- CVE-2026-76504: Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability
- CVE-2026-76460: Cisco Identity Services Engine Incorrect Use of Privileged APIs Vulnerability
Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.