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CVE-2026-20237

Cisco Identity Services Engine Hardening Release - Input Validation Vulnerabilities

Published: Sep 16, 2026Updated: Sep 18, 2026 Sources: CVE List NVDCWE-20
9.1CRITICAL
NVD MITRE
EPSS Score
0.3%
Top 73.9%
CISA KEV
Not in KEV
Exploits
0 Known
Remediation
No Fix Available
Self-Check
Not available

Description

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Identity Services Engine (ISE) and Cisco ISE Passive Identity Connector (ISE-PIC), engineering teams have conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20237 are related to improper input validation issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-20.

In plain language

AI Act now

This is a critical flaw in Cisco Identity Services Engine Software and Cisco ISE Passive Identity Connector; businesses using either should treat it as urgent, although a fix has not been published.

Executive summary

CVE-2026-20237 is a critical improper-input-validation vulnerability (CWE-20) in Cisco Identity Services Engine Software and Cisco ISE Passive Identity Connector that requires high privileges and can affect other security boundaries.

If affected, business impact
Identity system takeoverSensitive access data exposureUnauthorized network changesService disruption

What to do now

  1. Confirm whether you run Cisco Identity Services Engine Software or Cisco ISE Passive Identity Connector, and identify the installed version.
  2. Ask your Cisco support contact or IT provider whether your version is affected; no fixed version has been published.
  3. Restrict and review high-level administrator access, including removing accounts that are no longer needed.
  4. Watch Cisco security advisories for the vendor's fix and install it once available.
May need vendor / contractor work

CVSS Vector Breakdown

AV:NAC:LPR:HUI:NS:CC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:HPrivileges Required
High
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
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Weaknesses

CWE-20

Affected Products

Cisco
commercial·USaka cisco systems inc., cisco systems
Cisco Identity Services Engine Software
Networking Infrastructure
Cisco ISE Passive Identity Connector
Networking Infrastructure

Exploitability

0 exploit sources identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Initial Access
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References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-ise-XU5EwX5T
sec.cloudapps.cisco.com
News mentions
1

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