langchain4j‑aideepin up to version 3.32.0 contains an insecure direct object reference in the CharacterMessageController. When an authenticated user supplies another user's message UUID to the knowledge‑embedding-ref, memory-embedding-ref, or graph-ref endpoints, the application returns that user's knowledge‑base chunks, long‑term memory text, and graph data. This flaw allows an authorized user to read data that belongs to another user, thereby violating confidentiality.

The vulnerable product is langchain4j‑aideepin from the moyangzhan organization. All releases up to and including version 3.32.0 are affected; higher‑version releases that include the patch are not affected.

The CVSS score of 6 indicates a medium severity risk. The EPSS score is not available, so the exploitation likelihood cannot be quantified from the public data. The flaw requires the user to be authenticated and to know or guess a valid UUID of another user. No known public exploits or KEV listing exist. Because the flaw permits data disclosure, organizations with sensitive user data should treat this as a moderate but actionable threat.