SimpleChat, a secure AI conversation application, has a user‑IDOR flaw in its user‑info and user‑profile‑image endpoints, allowing an authenticated user to read another user's Cosmos DB record. The affected data include email addresses, display names, and profile images, resulting in a confidentiality compromise for other users. The vulnerability does not provide code execution or privilege escalation, but it exposes personally identifiable information that could be abused for phishing or social engineering.

Microsoft SimpleChat versions prior to 0.241.203 are vulnerable. The flaw exists in the GET /api/user/info/<user_id> and GET /api/user/profile-image/<user_id> handlers located in application/single_app/route_backend_users.py. Upgrading to 0.241.203 or later fixes the lack of object‑level authorization.

The CVSS score of 4.3 indicates a moderate severity impact restricted to confidentiality. The EPSS score of < 1% indicates a very low exploitation probability, and the vulnerability is not listed in the CISA KEV catalog, suggesting it is not a priority for widespread exploitation. The likely attack vector is authenticated requests to the vulnerable endpoints, which low‑privilege users can easily construct. Because the issue hinges solely on missing access checks, there is no dependency on external conditions or additional data to exploit the flaw.