Actively exploited · Published Mar 4, 2026 · Assigned by cisco
CVE-2026-20131Cisco Secure Firewall Management Center Software Remote Code Execution Vulnerability
Critical 10.0 Exploited Ransomware
In plain English
A critical-severity unsafe deserialization in Cisco Secure Firewall Management Center (FMC) from Cisco. Attackers are actively exploiting it in the wild (listed by CISA on March 19, 2026). It has been used in ransomware campaigns. The chance it is exploited in the next 30 days is estimated at 44.4% (higher than 99% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA guidance
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Federal agencies must remediate by Mar 22, 2026.
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco Secure Firewall Management Center (FMC) | 7.0.07.0.0.17.0.17.1.06.4.0.137.0.1.16.4.0.147.1.0.1 |
Weakness: CWE-502 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H