The vulnerability is an insecure direct object reference that lets an authenticated user retrieve the chat history of any character identified by its UUID. By issuing a GET request to /character/{uuid}, the service returns the victim’s questions, AI answers and any associated attachment or audio URLs because the code that resolves the character details does not verify that the requesting user owns the character. This allows attackers to read confidential content from other users, exposing sensitive conversation data.

The affected product is langchain4j-aideepin provided by moyangzhan. Versions prior to 3.31.0 are impacted. No specific patch level is listed beyond the requirement to upgrade to 3.31.0 or later.

The CVSS score of 6 indicates a moderate severity for this IDOR. Exploitation requires only that the attacker be authenticated; the vulnerability does not require elevated privileges or special network access. The EPSS score is not available, and the vulnerability is not listed in CISA’s KEV catalog, but the lack of an ownership check means any logged‑in user can expose another user’s data. The malicious actor could harvest conversation history and media, potentially compromising privacy and trust in the application.