CVE-2026-20131

CRITICALPre-NVD 10.010.0—
EchelonGraph scoreHIGH confidence

Score elevated to 10.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-03-19), indicating real-world exploitation has been confirmed by US federal agencies. a secondary CVSS source baseline 10.0 retained for reference (NVD's own analysis pending). Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, secondary
Trending — 4 sources updated this weekExploited in the wild
10.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 28%CVSS: 10.0Exploit: cisa kev · ssvc active · kev ransomware · epss top5pctExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
10.0
EG Score
10.0(high)
EG Risk
100(Act)
EG Risk 100/100SSVC: Act

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity100% × 45%
Exploitation100% × 40%
Automatability100% × 15%
Action: Fix now — active exploitation, automatable, high impact.
EPSS PROB
28%
EPSS %ILE
98%
KEV
⚠ Exploited

Published

March 4, 2026

Last Modified

June 17, 2026

Advisory Details (1)

Auto-updated Jul 27, 2026
No patch confirmed yet.
generic

Cisco Secure Firewall Management Center Software Remote Code Execution Vulnerability

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-rce-NKhnULJh

Vendor Advisories for CVE-2026-20131(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 23× in last 7d / 23× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-29 19:27 UTCCISA KEV update
  2. 2026-07-29 18:48 UTCGHSA enrichment
  3. 2026-07-29 15:00 UTCGHSA enrichment
  4. 2026-07-29 11:12 UTCGHSA enrichment
  5. 2026-07-29 07:23 UTCGHSA enrichment
  6. 2026-07-29 03:36 UTCGHSA enrichment
  7. 2026-07-28 23:47 UTCGHSA enrichment
  8. 2026-07-28 19:59 UTCGHSA enrichment
  9. 2026-07-28 16:09 UTCEG score recompute
  10. 2026-07-28 16:09 UTCGHSA enrichment
  11. 2026-07-28 12:20 UTCGHSA enrichment
  12. 2026-07-28 08:31 UTCGHSA enrichment
  13. 2026-07-28 04:41 UTCGHSA enrichment
  14. 2026-07-28 00:53 UTCGHSA enrichment
  15. 2026-07-27 21:05 UTCEG score recompute
  16. 2026-07-27 21:05 UTCGHSA enrichment
  17. 2026-07-27 19:24 UTCCISA KEV update
  18. 2026-07-27 17:17 UTCEG score recompute
  19. 2026-07-27 17:17 UTCGHSA enrichment
  20. 2026-07-27 17:17 UTCCISA KEV update
  21. 2026-07-27 14:13 UTCEPSS rescore
  22. 2026-07-27 12:54 UTCEG score recompute
  23. 2026-07-27 12:54 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2026-20131?
CVE-2026-20131 is a critical vulnerability published on March 4, 2026. 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…
When was CVE-2026-20131 disclosed?
CVE-2026-20131 was first published in the National Vulnerability Database on March 4, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-20131 actively exploited?
Yes. CISA added CVE-2026-20131 to the Known Exploited Vulnerabilities catalog on March 19, 2026, affecting Cisco Secure Firewall Management Center (FMC). KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2026-20131?
CVE-2026-20131 has a CVSS v3 base score of 10.0 (NVD).
Which products are affected by CVE-2026-20131?
CVE-2026-20131 affects Cisco Secure Firewall Management Center (FMC). The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2026-20131?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-20131, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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