CVE-2026-92567 in tduck-survey-form
Summary
by MITRE • 09/17/2026
TDuck survey form through version 5.0 contains an authorization bypass vulnerability in the POST /user/form/data/update endpoint that allows authenticated users to overwrite other users' form submission data. Attackers can discover submission identifiers allocated in narrow ranges and modify arbitrary form responses containing personal data by sending update requests without ownership validation.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/17/2026
The TDuck survey platform, specifically through version 5.0, suffers from a critical authorization bypass vulnerability within its core functionality for managing user-generated content. This flaw resides in the POST /user/form/data/update endpoint, which is designed to allow users to modify their own form submissions. However, the implementation fails to enforce proper ownership validation when processing these update requests. Instead of verifying that the authenticated user initiating the request owns the specific form submission being modified, the system relies on a predictable or easily discoverable identifier scheme for form data entries. This architectural weakness allows any authenticated user to manipulate records belonging to other users by simply guessing or iterating through valid submission identifiers.
The technical nature of this vulnerability is classified as an Insecure Direct Object Reference (IDOR), which corresponds to CWE-639 in the Common Weakness Enumeration standard. The root cause lies in the server-side logic that accepts a form submission identifier from the client request and directly applies it to update the corresponding database record without checking if the current session's user context matches the owner of that data. Because these identifiers are allocated within narrow ranges, they exhibit low entropy and high predictability. An attacker can systematically enumerate valid IDs by sending sequential requests or leveraging known patterns in how TDuck assigns these unique keys during form creation or submission processes. This lack of randomness makes brute-force enumeration trivial for an automated script.
The operational impact of this vulnerability is severe due to the sensitive nature of data typically collected through survey forms. Since TDuck is often used by organizations, educational institutions, and businesses to gather personal information such as names, contact details, demographic data, or even health-related inquiries, unauthorized modification constitutes a significant breach of confidentiality and integrity. An attacker can overwrite arbitrary form responses with malicious content, false statements, or fabricated data. This not only compromises the privacy rights of individual respondents but also undermines the reliability of aggregated survey results for administrators who rely on this data for decision-making processes. In scenarios where surveys are used for compliance reporting or academic research, such tampering could lead to legal liabilities and reputational damage.
From a threat modeling perspective aligned with the MITRE ATT&CK framework, this vulnerability facilitates actions categorized under T1078 Valid Accounts, as it requires initial authentication but then abuses those credentials to access unauthorized resources. It also aligns with T1565 Data Manipulation, where an attacker alters stored data to achieve malicious goals without necessarily deleting or encrypting it for ransomware purposes. The ability to silently modify existing records makes detection difficult through standard logging mechanisms unless detailed audit trails specifically tracking ownership changes are implemented and monitored.
To mitigate this vulnerability, immediate remediation should focus on implementing strict object-level access controls at the application layer. Developers must ensure that every request modifying a form submission includes server-side validation confirming that the authenticated user is the legitimate owner of the target record. This can be achieved by joining the current session's user ID with the ownership field in the database query used to update the data, ensuring updates only proceed if both identifiers match. Additionally, replacing predictable sequential IDs with cryptographically secure random identifiers or UUIDs would significantly increase the difficulty for attackers attempting to enumerate valid targets through brute force methods.
Beyond immediate code fixes, organizations should adopt a defense-in-depth strategy by implementing rate limiting on the affected endpoint to prevent rapid enumeration attempts and deploying Web Application Firewalls that can detect anomalous patterns of access to non-owned resources. Regular security audits focusing on authorization logic are essential to identify similar flaws in other endpoints. For existing deployments running version 5.0 or earlier, upgrading to a patched version is imperative if available from the vendor. Until an official patch is applied, administrators should restrict public-facing access to survey forms where possible and monitor logs for unusual spikes in update requests targeting different user IDs within short timeframes.