CVEvulnerability
CVE-2026-20131
CISA Known Exploited Vulnerability
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)
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.
- Added to KEV
- 2026-03-19
- Remediation due
- 2026-03-22
- Ransomware use
- Known
- 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.
- Notes
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-rce-NKhnULJh ; https://nvd.nist.gov/vuln/detail/CVE-2026-20131
- Status
- Analyzed
- Published
- 2026-03-04
- Last modified
- 2026-06-17
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 10.0 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- Weaknesses
- CWE-502
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 configurations
• cisco secure firewall management center 6.4.0.13
• cisco secure firewall management center 6.4.0.14
• cisco secure firewall management center 6.4.0.15
• cisco secure firewall management center 6.4.0.16
• cisco secure firewall management center 6.4.0.17
• cisco secure firewall management center 6.4.0.18
• cisco secure firewall management center 7.0.0
• cisco secure firewall management center 7.0.0.1
• cisco secure firewall management center 7.0.1
• cisco secure firewall management center 7.0.1.1
• cisco secure firewall management center 7.0.2
• cisco secure firewall management center 7.0.2.1
• cisco secure firewall management center 7.0.3
• cisco secure firewall management center 7.0.4
• cisco secure firewall management center 7.0.5
• cisco secure firewall management center 7.0.6
• cisco secure firewall management center 7.0.6.1
• cisco secure firewall management center 7.0.6.2
• cisco secure firewall management center 7.0.6.3
• cisco secure firewall management center 7.0.7
• cisco secure firewall management center 7.0.8
• cisco secure firewall management center 7.0.8.1
• cisco secure firewall management center 7.1.0
• cisco secure firewall management center 7.1.0.1
• cisco secure firewall management center 7.1.0.2
• cisco secure firewall management center 7.1.0.3
• cisco secure firewall management center 7.2.0
• cisco secure firewall management center 7.2.0.1
• cisco secure firewall management center 7.2.1
• cisco secure firewall management center 7.2.2
• cisco secure firewall management center 7.2.3
• cisco secure firewall management center 7.2.3.1
• cisco secure firewall management center 7.2.4
• cisco secure firewall management center 7.2.4.1
• cisco secure firewall management center 7.2.5
• cisco secure firewall management center 7.2.5.1
• cisco secure firewall management center 7.2.5.2
• cisco secure firewall management center 7.2.6
• cisco secure firewall management center 7.2.7
• cisco secure firewall management center 7.2.8
• cisco secure firewall management center 7.2.8.1
• cisco secure firewall management center 7.2.9
• cisco secure firewall management center 7.2.10
• cisco secure firewall management center 7.2.10.1
• cisco secure firewall management center 7.2.10.2
• cisco secure firewall management center 7.3.0
• cisco secure firewall management center 7.3.1
• cisco secure firewall management center 7.3.1.1
• cisco secure firewall management center 7.3.1.2
• cisco secure firewall management center 7.4.0
• cisco secure firewall management center 7.4.1
• cisco secure firewall management center 7.4.1.1
• cisco secure firewall management center 7.4.2
• cisco secure firewall management center 7.4.2.1
• cisco secure firewall management center 7.4.2.2
• cisco secure firewall management center 7.4.2.3
• cisco secure firewall management center 7.4.2.4
• cisco secure firewall management center 7.4.3
• cisco secure firewall management center 7.4.4
• cisco secure firewall management center 7.4.5
… and 11 more
Related
Weakness · CWE (1)
- CWE-502 Deserialization of Untrusted Data weakness
References
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-rce-NKhnULJh Vendor Advisory
- https://aws.amazon.com/blogs/security/amazon-threat-intelligence-teams-identify-interlock-ransomware-campaign-targeting-enterprise-firewalls/ Technical Description
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20131 US Government Resource