U.S. CISA adds a flaw in Cisco FMC and Cisco SCC Firewall Management to its Known Exploited Vulnerabilities catalog
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2026-20131 | Unauthenticated Java Deserialization RCE in Cisco FMC and SCC CVE-2026-20131 is a deserialization of untrusted data flaw (CWE-502) in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management. An unauthenticated, remote attacker can trigger it by sending crafted serialized data to the exposed management interface. Successful exploitation allows the attacker to execute arbitrary Java code as root on the affected device, giving full control of the central platform that manages Cisco firewall policy. Any organization running FMC or managing firewalls through SCC is potentially affected; specific version ranges have not yet been published in the available data. The flaw was added to CISA KEV on 2026-03-19 with known ransomware use, and EPSS assigns a ~31% probability of exploitation within 30 days (98th percentile), though no public proof-of-concept is known. Do: Check Cisco's advisory for fixed releases and upgrade all FMC and SCC-managed deployments as soon as patched versions are identified, since version ranges are not yet in this data; until patched, restrict the FMC/SCC web-based management interface to trusted management networks or VPN access. Given the CISA KEV listing (added 2026-03-19) with known ransomware use, treat this as a high-priority patch and confirm whether BOD 22-01 remediation deadlines apply to your organization. | 10.0 | 33% | KEV ransomware |
| largetens of thousands of FMC/SCC management deployments (10k–100k systems), with a smaller subset of management interfaces internet-exposed |
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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 of 10.0), to its Known Exploited Vulnerabilities (KEV) catalog.
“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.” reads the advisory. “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.”
The vulnerability is a remote code execution flaw that resides in Cisco Secure FMC’s web interface and allows unauthenticated remote attackers to exploit insecure Java deserialization and execute arbitrary code as root by sending a crafted serialized object.
The networking giant addressed the flaw in early March 2026.
The Interlock ransomware group has been exploiting this critical zero-day RCE vulnerability since late January.
Interlock ransomware group has been active since September 2024, it has targeted multiple organizations, including DaVita, Kettering Health, and Texas Tech University. Recently, researchers observed a new AI-assisted malware strain called Slopoly used in its operations.
Amazon researchers observed the Interlock group exploiting the CVE-2026-20131 flaw 36 days before disclosure, starting on January 26, 2026. This gave attackers time to compromise targets before detection. The activity was uncovered via honeypots and shared with Cisco to aid in the investigation and protect customers.
According to Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities, FCEB agencies have to address the identified vulnerabilities by the due date to protect their networks against attacks exploiting the flaws in the catalog.
Experts also recommend that private organizations review the Catalog and address the vulnerabilities in their infrastructure.
CISA orders federal agencies to fix the vulnerability by March 22, 2026.
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