Critical severity · published Mar 4, 2026
CVE-2026-20131
Cisco Secure Firewall Management Center Software Remote Code Execution Vulnerability
RansomwareIn wildKEV
10.0
CVSS
43.2%
EPSS
Yes
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)43.2% · higher than 99% of CVEs
Exploited in the wildYes
CISA KEVListed Mar 19, 2026
Federal remediation dueMar 22, 2026
Ransomware campaign useKnown
Affected products
Which versions
CS
Cisco Secure Firewall Management Center (FMC) · Cisco
7.0.0; 7.0.0.1; 7.0.1; 7.1.0; 6.4.0.13; 7.0.1.1; +34 more · source: vendor
SF
Secure Firewall Management Center · Cisco
6.4.0.13; 6.4.0.14; 6.4.0.15; 6.4.0.16; 6.4.0.17; 6.4.0.18; +34 more · source: NVD
SF
Secure Firewall Management Center (FMC) · Cisco
All versions, or not specified · source: KEV
In the news
VulnerabilityCritical
CISA orders feds to patch max-severity Cisco flaw by Sunday
The Cybersecurity and Infrastructure Security Agency (CISA) has ordered federal agencies to patch a maximum-severity vulnerability, CVE-2026-20131, in Cisco Secure Firewall Management Center (FMC) by Sunday, March 22. [...]
Mar 20, 2026·BleepingComputer
VulnerabilityCritical
Cisco FMC flaw was exploited by Interlock weeks before patch (CVE-2026-20131)
A critical vulnerability (CVE-2026-20131) in Cisco Secure Firewall Management Center (FMC) that Cisco disclosed and patched in early March 2026 has been exploited as a zero-day by the Interlock ransomware gang, Amazon CISO and VP of Security Engineering CJ Moses revealed. “Our research [using Amazon’s MadPot system of honeypots] found that Interlock was exploiting this vulnerability 36 days before its public disclosure, beginning January 26, 2026,” he said on Wednesday. CVE-2026-20131 exploited as zero-day for … More →
The post Cisco FMC flaw was exploited by Interlock weeks before patch (CVE-2026-20131) appeared first on Help Net Security .
Mar 20, 2026·Help Net Security
VulnerabilityCritical
U.S. CISA adds a flaw in Cisco FMC and Cisco SCC Firewall Management to its Known Exploited Vulnerabilities catalog
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) adds a flaw in Cisco FMC and Cisco SCC Firewall Management to its Known Exploited Vulnerabilities catalog. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added a flaw in Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management, tracked as CVE-2026-20131 (CVSS score […]
Mar 19, 2026·Security Affairs
VulnerabilityHigh
CISA Adds One Known Exploited Vulnerability to Catalog
CISA has added one new vulnerability to its Known Exploited Vulnerabilities (KEV) Catalog , based on evidence of active exploitation.
CVE-2026-20131 Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data Vulnerability
This type of vulnerability is a frequent attack vector for malicious cyber actors and poses significant risks to the federal enterprise.
Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities established the KEV Catalog as a living list of known Common Vulnerabilities and Exposures (CVEs) that carry significant risk to the federal enterprise. BOD 22-01 requires Federal Civilian Executive Branch (FCEB) agencies to remediate identified vulnerabilities by the due date to protect FCEB networks against active threats. See the BOD 22-01 Fact Sheet for more information.
Although BOD 22-01 only applies to FCEB agencies, CISA strongly urges all organizations to reduce their exposure to cyberattacks by prioritizing timely remediation of KEV Catalog vulnerabilities as part of their vulnerability management practice. CISA will continue to add vulnerabilities to the catalog that meet the specified criteria .
Mar 19, 2026·CISA Advisories
VulnerabilityCritical
Interlock group exploiting the CISCO FMC flaw CVE-2026-20131 36 days before disclosure
The Interlock ransomware group has exploited a Cisco FMC zero-day RCE vulnerability in attacks since late January. The Interlock ransomware group has been exploiting a critical zero-day RCE vulnerability, tracked as CVE-2026-20131 (CVSS score of 10.0), in Cisco Secure Firewall Management Center (FMC) since late January. The vulnerability is a remote code execution flaw that […]
Mar 19, 2026·Security Affairs
VulnerabilityCritical
[CISA KEV] CVE-2026-20131: Cisco Secure Firewall Management Center (FMC) - 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) 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.
SFSecure Firewall Management Center (FMC)CVE-2026-20131
Mar 19, 2026·CISA KEV
Affected product
CS
Cisco Secure Firewall Management Center (FMC)
Cisco
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-20131
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-20131
CISA KEV catalogue
https://www.cisa.gov/known-exploited-vulnerabilities-catalog
sec.cloudapps.cisco.com
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-rce-NKhnULJh
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