critical Known exploitedREV. 01

CVE-2026-20131Cisco Secure Firewall Management Center — deserialization to root

The web management interface of Cisco Secure Firewall Management Center rebuilds a Java object straight from the request, so an unauthenticated attacker can send a crafted one and run code as root on the box that governs the firewall estate.

YOUR NEXT MOVE

Apply Cisco advisory cisco-sa-fmc-rce-NKhnULJh now; an Interlock ransomware campaign targets this, so treat an exposed management centre as compromised.

Read the risk

THE VITAL STATS
CVSS score
10.0/ 10
CVSS v3.1
EPSS probability
33%
Likelihood of exploitation
Attack complexity
Low
Conditions needed to exploit
Known exploited
Yes — CISA KEV
CVE published
2026-03-04
Added to KEV
2026-03-19
Exploit published
Not recorded
Confidence
high
Kill chain
initial access
MITRE ATT&CK
T1190
Severity
critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Attacker needsNetwork access to the web management interface; no credentials needed.

Behind the card

4 REFERENCES
Field-level provenanceTRACE THE SOURCES +

Which source supports each field, when it was retrieved, and who extracted it.

FieldsSourceRetrievedExtractorConfidence
cvss, exploitation.attack_complexity, exploitation.exploit_available, references, published_atnvd.nist.gov2026-09-24scrty-crds-pipeline/0.1high
exploitation.known_exploited, exploitation.kev_addedcisa.gov2026-09-24scrty-crds-pipeline/0.1high
epssapi.first.org2026-09-24scrty-crds-pipeline/0.1high
title, summary, severity, remediation, mitre_attack, kill_chain, recommended_action, confidence, tags, exploitation.prerequisitesnvd.nist.gov2026-09-24claude-codehigh

Printing history

THE RECORD
  1. r1Initial base card

First printing. This card has not been reprinted since publication.

crds:cve-2026-20131 · CRDS 0.1 · Issued 2026-09-24