CVE-2026-111707
Deferred Deferred - Pending Action

99AI Chat Message Exposure via IDOR Vulnerability

Publication date: 2026-10-16

Last updated on: 2026-10-16

Assigner: VulnCheck

Description
99AI through 4.3.0 contains an insecure direct object reference vulnerability that allows unauthenticated attackers to read other users' chat messages because querySingleChat lacks an owner check. Attackers can send a fingerprint header to obtain a visitor JWT and iterate sequential chatId values to retrieve other users' message content and task data.

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Meta Information

Published
2026-10-16
Last Modified
2026-10-16
Generated
2026-10-19
AI Q&A
2026-10-16
EPSS Evaluated
2026-10-18
NVD
CVE-2026-111707
EUVD
EUVD-2026-102999

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
vastxie 99AI 0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-639 The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

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Executive Summary

This vulnerability is an insecure direct object reference in 99AI versions up to 4.3.0. It allows unauthenticated attackers to read other users' chat messages by exploiting a missing owner check in the querySingleChat function. Attackers can send a fingerprint header to obtain a visitor JWT and then iterate through sequential chatId values to retrieve private message content and task data from other users.

Detection Guidance

Detecting this vulnerability requires checking for unauthenticated access to chat messages via sequential chatId values. Monitor network traffic for requests to /querySingleChat with varying chatId parameters. Look for JWT tokens in fingerprint headers without proper authentication. Check application logs for unusual sequential access patterns to chat endpoints.

Impact Analysis

This vulnerability could allow attackers to access your private chat messages and task data without authentication. If you use 99AI, your sensitive conversations and information could be exposed. Attackers might exploit this to steal data, impersonate users, or gather intelligence for further attacks.

Compliance Impact

This vulnerability likely violates GDPR and HIPAA due to unauthorized access to personal and sensitive data. GDPR requires protecting personal data, and HIPAA mandates safeguarding protected health information. The exposure of chat messages and task data could lead to compliance breaches, legal penalties, and reputational damage for organizations using 99AI.

Mitigation Strategies

Immediately update 99AI to the latest version beyond 4.3.0. Implement strict access controls to ensure chatId values can only be accessed by their owners. Add authentication checks to the /querySingleChat endpoint. Disable or restrict the use of fingerprint headers for JWT generation. Monitor and block sequential access attempts to chat endpoints.

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