CVE-2026-129454 in Zr.Admin.NET
Summary
by MITRE • 11/15/2026
Zr.Admin.NET commit 85cff6a through commit eb9228a contains an insecure direct object reference vulnerability in GET /workflow/instance/{instanceId} that lets logged-in users view others' workflow instances. Authenticated low-privilege attackers can enumerate sequential instance IDs to read other users' approval requests, including submitted form contents, applicant details and approval records.
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Analysis
by VulDB Data Team • 11/15/2026
The identified security flaw resides within the Zr.Admin.NET framework, specifically affecting versions between commit 85cff6a and commit eb9228a. This vulnerability is classified as an Insecure Direct Object Reference (IDOR), a critical category of access control failure where an application exposes internal implementation objects such as database keys or file names to end users without proper verification. The specific point of exploitation is the HTTP GET endpoint /workflow/instance/{instanceId}. Under normal secure design principles, when a user requests data associated with a workflow instance, the server must verify that the requesting user has explicit authorization to view that specific resource based on their role and ownership status. However, in this vulnerable implementation, the backend logic relies solely on the sequential numeric value provided in the URL path parameter without performing any additional checks against the authenticated session's permissions or data ownership records.
This architectural oversight allows an attacker who possesses valid authentication credentials with low-level privileges to bypass intended access controls. By manipulating the instanceId parameter, a logged-in user can iterate through sequential identifiers to enumerate and retrieve workflow instances belonging to other users within the system. The operational impact is significant as it leads to unauthorized disclosure of sensitive business data. Attackers can extract detailed information including submitted form contents which may contain personally identifiable information or proprietary business logic, applicant details such as names and contact information, and internal approval records that reveal organizational hierarchy and decision-making processes. This capability effectively turns a standard workflow management feature into a tool for comprehensive data exfiltration by any authenticated user, regardless of their administrative level.
From a classification perspective, this vulnerability aligns directly with CWE-639: Authorization Bypass Through User-Controlled Key, which describes scenarios where an application uses client-supplied input to access resources without verifying if the user is authorized for that specific resource. Furthermore, in terms of offensive security tactics, this behavior maps to MITRE ATT&CK technique T1078: Valid Accounts, as it leverages legitimate credentials to gain unauthorized access, and potentially T1530: Data from Cloud Storage or Internal Shared Drive if the workflow data is stored externally, though primarily it represents a direct violation of confidentiality through improper authorization checks. The sequential nature of the IDs also facilitates efficient enumeration attacks, allowing attackers to systematically harvest large volumes of sensitive records with minimal effort once initial access is established.
To mitigate this vulnerability, developers must implement strict object-level authorization checks within the controller or service layer handling the /workflow/instance/{instanceId} endpoint. This involves retrieving the workflow instance associated with the provided ID and verifying that the currently authenticated user's identity matches the owner of the instance or holds a role explicitly permitted to view it. If the check fails, the server should return an HTTP 403 Forbidden response rather than exposing the data. Additionally, adopting non-sequential identifiers such as UUIDs for workflow instances can reduce the efficiency of enumeration attacks by making ID guessing computationally infeasible, although this is a secondary defense and does not replace the need for proper authorization logic. Regular security code reviews focusing on access control patterns and automated testing using tools that simulate unauthorized data access are recommended to prevent similar flaws in future development cycles.