Auth bypass in Moyangzhan Langchain4j-Aideepin
CVE-2026-121938
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.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/moyangzhan/langchain4j-aideepin/issues/116 (issue-tracking)
- hackmd.io/@hieuPenguinnn/langchain4j-aideepin-character-conversation-cross-user… (third-party-advisory)
- github.com/moyangzhan/langchain4j-aideepin/pull/117 (issue-tracking, patch)
- github.com/moyangzhan/langchain4j-aideepin/commit/9b2fee6b66836a0efd5599cfcddd0… (patch)
- github.com/moyangzhan/langchain4j-aideepin/blob/v3.30.0/server/adi-common/src/m… (technical-description)
- www.vulncheck.com/advisories/langchain4j-aideepin-before-3.31.0-idor-via-get-ch… (third-party-advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0
Frequently asked questions
- What is CVE-2026-121938?
- CVE-2026-121938 is a medium-severity vulnerability in Moyangzhan Langchain4j-Aideepin, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 5.3/10. Published 2026-11-04.
- How severe is CVE-2026-121938?
- Medium severity. CVSS v3 base score is 5.3 out of 10.