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CVE-2026-20131

Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data Vulnerability

Cisco Secure Firewall Management Center (FMC) CWE-502

A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to execute arbitrary Java code as root on an affected device. This vulnerability is due to insecure deserialization of a user-supplied Java byte stream. An attacker could exploit this vulnerability by sending a crafted serialized Java object to the web-based management interface of an affected device. A successful exploit could allow the attacker to execute arbitrary code on the device and elevate privileges to root. Note: If the FMC management interface does not have public internet access, the attack surface that is associated with this vulnerability is reduced.

CVSS Score
10
Critical
EPSS — Exploit Probability
43%
Riskier than 99% of all CVEs · checked 2026-10-17
Exploitation
Confirmed in the wild
Used in ransomware campaigns
Remediation
Patch available
Federal deadline 2026-03-22
CISA required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Deadline for federal agencies: 2026-03-22.

NVD entry Vendor patch PoC / advisory CISA KEV

18 articles across 9 outlets · first covered Apr 2, 2026 · latest May 18, 2026

Associated threat actors

InterLock

Coverage timeline

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