CVE-2026-20286 in Identity Services Engine
Summary
by MITRE • 09/16/2026
A vulnerability in the web-based management interface of Cisco Identify Services Engine (ISE) could allow an authenticated, remote attacker to modify parts of the configuration on an affected device.
This vulnerability is due to the lack of server-side validation of Administrator permissions. An attacker could exploit this vulnerability by submitting a crafted HTTP request to an affected system. A successful exploit could allow the attacker to modify descriptions of files on a specific page. To exploit this vulnerability, an attacker would need valid Administrator credentials.
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Analysis
by VulDB Data Team • 09/17/2026
The identified security flaw resides within the web-based management interface of Cisco Identity Services Engine (ISE), specifically affecting systems where administrative access is granted through authenticated sessions. This vulnerability stems from a fundamental architectural oversight in how the application handles permission validation for specific configuration actions. While the system correctly requires authentication to enter the management portal, it fails to perform adequate server-side verification when processing requests intended to modify file descriptions or similar metadata within the interface. Consequently, an attacker who has obtained valid Administrator credentials can bypass logical access controls by crafting and submitting malicious HTTP requests that target these unprotected endpoints. This lack of proper authorization checks allows for unauthorized modification of configuration elements, undermining the integrity of the administrative state even when the user is technically authorized to log in but potentially restricted from making such specific changes or if the privilege escalation logic is flawed.
From a technical perspective, this issue represents a classic case of broken access control where the application relies on client-side restrictions or insufficient server-side validation rather than enforcing strict role-based permissions for every action. The operational impact involves the ability to alter descriptions and potentially other metadata associated with files managed by ISE. While the immediate description suggests modification of file descriptions, in enterprise network environments, such interfaces often manage critical security policies, certificates, and authentication profiles. Unauthorized modifications could lead to configuration drift, misconfiguration of identity services, or serve as a vector for further exploitation if these modified elements are referenced by other system components. This compromises the reliability of the Identity Services Engine, which is central to enforcing network access control and policy enforcement in many organizations.
This vulnerability aligns with CWE-269, Improper Privilege Control, specifically regarding insufficient verification of administrative rights during state-changing operations. It also maps to MITRE ATT&CK technique T1078, Valid Accounts, as the exploitation requires legitimate credentials but abuses them through flawed permission logic rather than credential theft alone. The attack vector is classified as remote with low complexity due to the need for valid admin access, yet it poses a significant risk because administrative accounts are high-value targets and often have broad privileges if other controls fail.
To mitigate this risk, organizations should ensure that their Cisco ISE deployments are updated to the latest recommended software versions provided by Cisco, which typically include patches for such authorization logic errors. Administrators must enforce strict access control policies, ensuring that only essential personnel hold Administrator-level credentials and that these accounts are protected with multi-factor authentication where supported. Additionally, network segmentation should be applied to restrict direct internet-facing exposure of management interfaces, limiting access to trusted internal networks or secure jump hosts. Regular auditing of administrative activity logs is also recommended to detect any unauthorized configuration changes promptly.