Exploited CVEs / Cisco / CVE-2026-20131
CVE-2026-20131
Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted, and the vulnerability is known to be used in ransomware campaigns. Federal agencies were required to remediate by 2026-03-22 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Cisco Security Advisories (PSIRT), linked below.
Actively exploited Cisco Secure Firewall Management Center (FMC) vulnerability, Critical severity, CVSS 10.0. Added to the CISA KEV catalog 2026-03-19.
Risk summary
Updated July 26, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2026-20131
Ransomware operators are exploiting this deserialization flaw in the web management interface of Cisco Secure Firewall Management Center and Security Cloud Control, which gives unauthenticated remote code execution at a maximum CVSS of 10.0. CISA confirmed exploitation on 2026-03-19. FMC holds policy and administrative control over your firewall estate, so a compromise here converts your perimeter defenses into the attacker's tooling.
Do this: Patch FMC and SCC Firewall Management immediately and make sure the management interface is unreachable from the internet.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2026-20131
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2026-20131
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
CISA required action
Federal (BOD 22-01) remediation due date: 2026-03-22 (past due).
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Official fix for CVE-2026-20131
The authoritative fix and affected-version list are published by the vendor. Find the Secure Firewall Management Center (FMC) advisory on Cisco Security Advisories (PSIRT).
Common questions about CVE-2026-20131
Is CVE-2026-20131 actively exploited?
Yes. CVE-2026-20131 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2026-03-19, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 28%. CISA also reports it is known to be used in ransomware campaigns.
What is the CISA deadline and required action for CVE-2026-20131?
CISA set the federal (BOD 22-01) remediation due date at 2026-03-22, which has passed; treat any unremediated system as overdue. The verbatim 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.
What fixes CVE-2026-20131?
The authoritative fix is in the vendor advisory: see Cisco Security Advisories (PSIRT) for the patched Secure Firewall Management Center (FMC) versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.
Can I ask my own AI about CVE-2026-20131?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-20131's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).
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