CVE-2026-20131
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Cisco Secure Firewall Management Center Software Remote Code Execution Vulnerability
rank 88 = 40 + 25 + 1 + 14 + 8
rank@v1 · act now
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.43166 · CISA KEV listed · without this subject the record ranks 48
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 10.0, from the CNA · without this subject the record ranks 63
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
rose on 2026-09-28 · without this subject the record ranks 87
How much of the world it touches
NVD CPE configurations
71 products in the CPE ranges · without this subject the record ranks 74
Someone else already set the date
CISA KEV remediation due date
CISA remediation date held · without this subject the record ranks 80
Hindsight · the state
Foresight · where to check next
This record is one instance of CWE-502, deserialization of untrusted data. The index holds 3512 prior instances of this class, 75 KEV-listed. The nearest of its KEV-listed records are drawn beside this. taxonomy@v1
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Harm, if it fires from the vector and the weakness
Written for the ticket you're about to file.
CISA KEV & Federal Remediation Deadline from the record and CISA
The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Ransomware campaign use known, 2026-03-19.
Affected & Fixed Versions as published
Show all 71 published ranges
A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.
$2.15M = $4.99M incident cost x 1 exposure x 0.43166 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Attack path
What it is stated by the CNA
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. receipt
Read the rest of the CNA's description
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.
NVD's analysis a second authority
- weakness
- CWE-502
- affected versions
- cisco secure firewall management center 6.4.0.13; cisco secure firewall management center 6.4.0.14; cisco secure firewall management center 6.4.0.15; and 68 more, listed in full below
- also scored by
- psirt@cisco.com 10 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
check it yourself sec.cloudapps.cisco.com receipt
Dated events
Movement the material steps
Show all 24 observations
24 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt
The pattern, elsewhere
This record is one instance of CWE-502, deserialization of untrusted data. The index holds 3512 prior instances of this class, 75 KEV-listed. The nearest of its KEV-listed records are drawn beside this. cwe-consequences@4.20
"Matches n of m" counts the attributes the two records can both be compared on: the CVSS metrics they share a version of, any weakness class beyond this one, and the vendor. fit-rules@v1
3512 records in this class held. The six above are drawn from the ones CISA has listed as exploited, ranked by how much of the record matches this one. That is why every one of them is KEV-listed: the pool is, so the colour on those spokes says nothing the pool has not already said.
No curated product neighbourhood is held for this product, so the records above are the nearest this index can name. The neighbourhood table covers a small set of products and is extended by hand.
Siblings and hubs
Records related to this one
None. No alias set, and nothing in the corpus cites this identifier or shares its product family within 60 days.
Browse the index from here
These are index-wide views, not findings about CVE-2026-20131.
What usually comes next
Everything above needs no account. What is below is work: assembling it, scoping it to your estate, watching it, and handing it to someone else.