Summary
| Parameter | Value |
|---|---|
| CVE ID | CVE-2026-20131 |
| Alert Source | CISA KEV - Active Exploitation |
| CVE Publication Year | 2026 |
| Date Published | 2026-03-19 |
| Vendor | Cisco |
| Product | Secure Firewall Management Center (FMC) |
| CVSS Score | 10.0 (critical) |
| EPSS Score | 0.6% (percentile: 68%) |
| CISA KEV | Yes - confirmed active exploitation |
| Ransomware | Yes - used in ransomware campaigns |
| Remediation Deadline | 2026-03-22 |
Vulnerability Description
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.
Required Actions
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Ransomware Warning
This vulnerability is actively exploited in ransomware campaigns. Immediate action is critical for your organization’s security.
Who Is Affected?
This vulnerability affects Secure Firewall Management Center (FMC) by Cisco. Check if your organization uses this software and requires updates.
Sources
Need help securing your systems? nFlo team offers vulnerability management and 24/7 SOC services. Contact us.
How can nFlo help?
If your organization uses products affected by this vulnerability, contact us. We can help with:
- Verifying whether your systems are at risk
- Implementing patches and risk mitigation
- Monitoring for exploitation attempts in your environment
Useful resources:
Frequently asked questions
What is the CVE-2026-20131 vulnerability?
CVE-2026-20131 is a security vulnerability discovered in Cisco's Secure Firewall Management Center (FMC). The vulnerability has been assigned a CVSS score of 10 (critical severity). Any organization using this product should immediately verify their exposure and take appropriate remediation steps.
Who is affected by CVE-2026-20131?
This vulnerability affects users of Cisco's Secure Firewall Management Center (FMC). Organizations using this solution should check whether their deployed version is vulnerable and apply available security patches or implement recommended workarounds.
How to protect against CVE-2026-20131?
Apply security patches released by Cisco or implement recommended workarounds. Regular vulnerability monitoring and prompt patch deployment are essential for effective protection against this type of threat.
What is the risk level of CVE-2026-20131?
The vulnerability has a CVSS score of 10 (critical severity). Successful exploitation could lead to compromise of organizational systems and data. CISA has added this vulnerability to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in production environments. This vulnerability is known to be used by ransomware groups, increasing the risk of significant financial and operational losses. Recommended remediation deadline: 2026-03-22.
Is CVE-2026-20131 actively exploited in the wild?
Yes, CISA has added this vulnerability to the Known Exploited Vulnerabilities (KEV) catalog, confirming its active exploitation in real-world attacks. Organizations should prioritize this vulnerability and deploy patches immediately.
