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CVE-2026-20131: Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data Vulnerability

CVSS: 10.0v3.1CriticalKEVRansomwareAnalyzed
Published 04-03-2026Last modified 14-08-2026
Open JSON

Vulnerability summary

CVE-2026-20131 is a critical (CVSS 10.0) Deserialization of Untrusted Data vulnerability in Cisco Secure Firewall Management Center (FMC). It is known to be exploited: CISA lists it, first on 19-03-2026. It has been used in ransomware campaigns. EPSS estimates a 43.17% chance of exploitation in the next 30 days, higher than 98.7% of scored vulnerabilities.

Overall risk
90/100
0100
Critical · default modelHow is this calculated?
CVSS score
10.0/10
010
Critical · v3.1 (CVE.org)
EPSS score
43.17%
0%100%
High · +9.79 pp in 30 days
KEVListedCISA
RansomwareKnown useFlagged by CISA
Public exploits0No public exploits recorded

Timeline

  1. 04-03-2026
    PublishedVulnerability first disclosed.
  2. 19-03-2026
    Added to CISA KEVCisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data Vulnerability
  3. 22-03-2026
    CISA remediation dueApply mitigations per vendor instructions.
  4. 14-08-2026
    Last modifiedVulnerability information updated.

Description

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 metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

43.17%

Chance of exploitation in the next 30 days

Percentile

99%

Versus all other CVEs

30-day change

+9.79 pp

From 33.38% on 21-09-2026

21-09-202621-10-2026
EPSS score
43.17%

Known exploited

Compare KEV catalogs
CISA KEVListed
Added
19-03-2026
Federal due date
22-03-2026
Ransomware

CISA 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. sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-rce-NKhnULJh nvd.nist.gov/vuln/detail/CVE-2026-20131

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Cisco2 products
  • cisco secure firewall management center (fmc)7.0.0 | 7.0.0.1 | 7.0.1 | 7.1.0 | 6.4.0.13 | 7.0.1.1 | 6.4.0.14 | 7.1.0.1 | 7.0.2 | 6.4.0.15 | 7.2.0 | 7.0.2.1 | 7.0.3 | 7.1.0.2 | 7.2.0.1 | 7.0.4 | 7.2.1 | 7.0.5 | 6.4.0.16 | 7.3.0 | 7.2.2 | 7.3.1 | 7.2.3 | 7.1.0.3 | 7.2.3.1 | 7.2.4 | 7.0.6 | 7.2.4.1 | 7.2.5 | 7.3.1.1 | 7.4.0 | 6.4.0.17 | 7.0.6.1 | 7.2.5.1 | 7.4.1 | 7.2.6 | 7.4.1.1 | 7.0.6.2 | 6.4.0.18 | 7.2.7 | 7.2.5.2 | 7.3.1.2 | 7.2.8 | 7.6.0 | 7.4.2 | 7.2.8.1 | 7.0.6.3 | 7.4.2.1 | 7.2.9 | 7.0.7 | 7.7.0 | 7.4.2.2 | 7.2.10 | 7.6.1 | 7.4.2.3 | 7.0.8 | 7.6.2 | 7.7.10 | 7.2.10.1 | 7.0.8.1 | 7.6.2.1 | 7.2.10.2 | 7.7.10.1 | 7.4.2.4 | 7.4.3 | 7.7.11 | 7.6.4 | 10.0.0 | 7.4.4 | 7.4.5
  • secure_firewall_management_center6.4.0.13 | 6.4.0.14 | 6.4.0.15 | 6.4.0.16 | 6.4.0.17 | 6.4.0.18 | 7.0.0 | 7.0.0.1 | 7.0.1 | 7.0.1.1 | 7.0.2 | 7.0.2.1 | 7.0.3 | 7.0.4 | 7.0.5 | 7.0.6 | 7.0.6.1 | 7.0.6.2 | 7.0.6.3 | 7.0.7 | 7.0.8 | 7.0.8.1 | 7.1.0 | 7.1.0.1 | 7.1.0.2 | 7.1.0.3 | 7.2.0 | 7.2.0.1 | 7.2.1 | 7.2.2 | 7.2.3 | 7.2.3.1 | 7.2.4 | 7.2.4.1 | 7.2.5 | 7.2.5.1 | 7.2.5.2 | 7.2.6 | 7.2.7 | 7.2.8 | 7.2.8.1 | 7.2.9 | 7.2.10 | 7.2.10.1 | 7.2.10.2 | 7.3.0 | 7.3.1 | 7.3.1.1 | 7.3.1.2 | 7.4.0 | 7.4.1 | 7.4.1.1 | 7.4.2 | 7.4.2.1 | 7.4.2.2 | 7.4.2.3 | 7.4.2.4 | 7.4.3 | 7.4.4 | 7.4.5 | 7.6.0 | 7.6.1 | 7.6.2 | 7.6.2.1 | 7.6.3 | 7.6.4 | 7.7.0 | 7.7.10 | 7.7.10.1 | 7.7.11 | 10.0.0

1 vendor · 2 products

References

3 links