Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessObtain high-privilege ISE admin credentials
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DeliveryReach ISE/ISE-PIC service over network
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ExploitSubmit crafted malformed input (CWE-20)
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ExecutionTrigger input-validation flaw across scope boundary
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ImpactCompromise confidentiality, integrity and availability of identity platform
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V2 - Validation and Business Logic Input validation, allowlisting
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| Exploitation Conditions | Requires the attacker to already hold high-privilege administrative access to a Cisco ISE or ISE-PIC node (PR:H) and network reachability to the affected ISE service (AV:N, no user interaction). No non-default feature toggle is named in the advisory - the flaws are grouped improper-input-validation issues (CWE-20) addressed in a hardening release across ISE/ISE-PIC. The dominant limiting factor is the administrative-credential prerequisite, which confines realistic exploitation to already-privileged insiders or post-compromise attackers who have obtained admin access; the value is that a scope change (S:C) can then extend impact beyond the vulnerable component. |
| Impact | This is a high-CVSS (9.1) issue whose real-world urgency is moderated by a critical limiting factor in its own vector: PR:H. Exploitation requires the attacker to already hold high-privilege (administrative) credentials on the Cisco ISE/ISE-PIC appliance, making this a near-trusted-attacker or post-compromise scenario rather than a spray-and-pray internet threat. The network vector (AV:N), low complexity (AC:L), no user interaction (UI:N), and scope change (S:C) with full C:H/I:H/A:H impact are what drive the score to critical. However, all impact values and the scope change are vendor-asserted through a grouped 'software hardening release' advisory that bundles multiple internally discovered CWE-20 input-validation flaws under one CVE - the description gives no per-flaw technical detail, so C:H/I:H/A:H should be read as an aggregate ceiling rather than a demonstrated single-flaw outcome. No EPSS score, no CISA KEV listing, and no public POC are present; combined with the fact that Cisco found these internally (not via observed exploitation), there is no evidence of active or imminent exploitation. No SSVC decision data was provided. Net: patch on a normal-to-elevated cadence for internet- or management-network-exposed ISE nodes, but the PR:H gate means this is a defense-in-depth / post-auth hardening priority, not an emergency for organizations with sound admin credential hygiene. |
| Exploit ScenarioDerived | An attacker who has already obtained (or been legitimately granted) high-privilege administrative access to a Cisco ISE or ISE-PIC node sends crafted, improperly validated input over the network to an ISE service, triggering one of the grouped CWE-20 flaws. Because the vector carries S:C, the resulting condition can affect resources beyond the vulnerable component, potentially compromising confidentiality, integrity, and availability of the identity/NAC platform. No public exploit code has been identified at time of analysis, and Cisco reports the issues were discovered through an internal security review rather than in-the-wild abuse. |
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Alert meAnalysisAIv1 – Sep 16, 2026
Improper input validation in Cisco Identity Services Engine (ISE) and Cisco ISE Passive Identity Connector (ISE-PIC) allows a remote attacker who already holds high-privilege administrative credentials to cause high confidentiality, integrity, and availability impact, with a scope change that may extend effects beyond the vulnerable component. Rated CVSS 9.1, this issue is moderated in practice by its PR:H prerequisite, which confines realistic exploitation to already-privileged insiders or post-compromise attackers; no public exploit code or active exploitation has been identified at time of analysis. Affected software is addressed by a Cisco hardening release, and the vendor advisory should be consulted for fixed releases.
RemediationAI
Patch available per vendor advisory; apply the Cisco hardening release described in cisco-sa-hardening-ise-XU5EwX5T, because the input data does not provide an exact fixed version number. Until the upgrade is completed, reduce exposure by enforcing least privilege and MFA for ISE and ISE-PIC administrative accounts, limiting management-plane access to trusted networks, and monitoring for anomalous administrative actions; these compensating controls mitigate the PR:H prerequisite but do not fix the underlying CWE-20 flaws and may add operational friction for administrators. Because exploitation requires existing high-privilege access, prioritize credential hygiene and post-compromise detection, and review the advisory for product-specific fixed releases.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 2 packages in euvd
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Technical ContextAI · show details
The root cause is grouped under CWE-20 (Improper Input Validation), a pillar weakness covering missing or incorrect validation of externally supplied data. Cisco's internal security review resulted in a hardening release that fixes multiple such issues in Cisco Identity Services Engine (ISE) and Cisco ISE Passive Identity Connector (ISE-PIC). CPE data identifies two affected product families: cpe:2.3:a:cisco:cisco_identity_services_engine_software and cpe:2.3:a:cisco:cisco_ise_passive_identity_connector, both with wildcard versions indicating no specific version range is provided in the available data. The CVSS vector (AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H) shows network reachability, low attack complexity, high privileges required, no user interaction, and a scope change, meaning successful exploitation could affect resources beyond the vulnerable component. Because these are grouped input-validation flaws, specific exploitation mechanics are not enumerated in the advisory, but the high CIA impact and scope change indicate potential for significant control-plane or data compromise once an attacker has administrative access.
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Severity by source
AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Network-reachable, low-complexity but gated behind high-privilege admin auth (PR:H); vendor-asserted scope change and full C/I/A impact accepted for the grouped bundle.
Primary rating from Vendor (cisco).
CVSS VectorVendor: cisco
DescriptionCVE.org
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.
Executive ViewAI
Cisco Identity Services Engine (ISE) and ISE Passive Identity Connector (ISE-PIC) contain a critical input validation vulnerability (CVE-2026-20237) that could allow an attacker with high-privilege administrative credentials to compromise the confidentiality, integrity, and availability of these systems, with potential scope change affecting connected network infrastructure. Because exploitation requires prior administrative access, the immediate risk is primarily from malicious insiders or attackers who have already breached privileged accounts, but a successful exploit could disrupt enterprise-wide authentication and authorization services, impacting business operations. Leadership should prioritize restricting administrative access and monitoring for anomalous activity while awaiting a vendor patch; no public exploit identified at time of analysis.
No vendor-released patch identified at time of analysis. Interim mitigations include: restricting administrative access to Cisco ISE/ISE-PIC to trusted networks and personnel, enforcing multi-factor authentication for all administrative accounts, implementing strict privilege management, monitoring logs for unusual administrative activity, and applying vendor-recommended hardening configurations. Network segmentation and continuous monitoring for indicators of compromise are also recommended.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Authentication bypass in Cisco Identity Services Engine (ISE) and ISE Passive Identity Connector lets an unauthenticated
Cisco ISE and Cisco ISE-PIC can be taken over by an unauthenticated, remote attacker who reaches the REST API web servic
Improper access control vulnerabilities in Cisco Identity Services Engine (ISE) and ISE Passive Identity Connector (ISE-
Remote, unauthenticated attackers with network access to Cisco Identity Services Engine (ISE) or ISE Passive Identity Co
Command injection in Cisco Identity Services Engine (ISE) and ISE Passive Identity Connector (PIC) allows authenticated
Authenticated remote command execution in Cisco Identity Services Engine (ISE) and ISE Passive Identity Connector (ISE-P
Cisco Identity Services Engine (ISE) and ISE Passive Identity Connector (ISE-PIC) contain multiple internally discovered
Information disclosure in Cisco Identity Services Engine (ISE) and ISE Passive Identity Connector (ISE-PIC) allows unaut
Improper privilege management in Cisco Identity Services Engine (ISE) and Cisco ISE Passive Identity Connector (ISE-PIC)
Path traversal in Cisco Identity Services Engine (ISE) and ISE Passive Identity Connector (ISE-PIC) allows a remote, aut
Unauthenticated path traversal in the Cisco ISE and ISE-PIC client provisioning download service allows a remote attacke
Unauthenticated remote attackers who can reach the Cisco Identity Services Engine guest portal can submit forged endpoin
EUVD-2026-81108
GHSA-8h74-5vrg-hj96
NVD
CVE.org
EPSS
Exploit-DB