---
id: CVE-2026-121938
title: 'langchain4j-aideepin before 3.31.0 IDOR via GET /character/{uuid}'
summary: >-
  langchain4j-aideepin before 3.31.0 contains an insecure direct object
  reference vulnerability that allows authenticated users to read other users'
  character-chat conversations by supplying their character uuid. Attackers can
  request GET …
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-639
vendor: moyangzhan
product: langchain4j-aideepin
affected:
  - langchain4j-aideepin < 3.31.0
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-04T18:50:02.027188Z'
exploitAvailable: true
published: '2026-11-04'
updated: '2026-11-04'
sourceUpdated: '2026-11-04T18:50:28.489Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-121938'
references:
  - url: 'https://github.com/moyangzhan/langchain4j-aideepin/issues/116'
  - url: >-
      https://hackmd.io/@hieuPenguinnn/langchain4j-aideepin-character-conversation-cross-user-idor
  - url: 'https://github.com/moyangzhan/langchain4j-aideepin/pull/117'
  - url: >-
      https://github.com/moyangzhan/langchain4j-aideepin/commit/9b2fee6b66836a0efd5599cfcddd05b80b05ca93
  - url: >-
      https://github.com/moyangzhan/langchain4j-aideepin/blob/v3.30.0/server/adi-common/src/main/java/com/moyz/adi/common/service/CharacterService.java#L105-L125
  - url: >-
      https://www.vulncheck.com/advisories/langchain4j-aideepin-before-3.31.0-idor-via-get-character-uuid
    label: >-
      VulnCheck Advisory: langchain4j-aideepin before 3.31.0 IDOR via GET
      /character/{uuid}
tags:
  - cve.org
  - exploit-available
ingestedAt: '2026-11-05T21:36:00.499Z'
epss: 0.00391
epssPercentile: 0.33435
---

## Overview

langchain4j-aideepin before 3.31.0 contains an insecure direct object reference vulnerability that allows authenticated users to read other users' character-chat conversations by supplying their character uuid. Attackers can request GET /character/{uuid}, which CharacterService.detail resolves without an ownership check, to obtain victims' questions, AI answers, and attachment and audio URLs.

## Affected

- `langchain4j-aideepin < 3.31.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.