CVE-2026-121938moyangzhan langchain4j-aideepin insecure direct object reference
CVE-2026-121938 is a insecure direct object reference in moyangzhan langchain4j-aideepin, rated medium (6.0 on CVSS 4.0).
Why this priority: Medium severity, with no exploitation signal.
Published · Updated · NVD status: Received
What it is
Changing an identifier in a request reaches another user's records.
How it is reached
An attacker can exploit it over the network, with an ordinary user account, and nobody has to click anything. Success also depends on conditions the attacker does not fully control.
What an attacker gains
A successful attack can read the data it protects. In practice, this kind of flaw lets an attacker reach data or actions their role should not allow.
Is it being exploited?
CISA's SSVC assessment notes a public proof of concept. EPSS estimates a 0.39% chance of exploitation activity in the next 30 days, higher than 34% of scored CVEs.
What to do
- Upgrade moyangzhan langchain4j-aideepin to 3.31.0 or later.
- Until it is patched, review who holds accounts that can reach it.
Description from NVD
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.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Permission checks in APIs and admin surfaces. The flaw sits between one role or tenant and another.
- Multi-tenant services. The flaw sits between one role or tenant and another.
Trust boundaries in play
- Authenticated network access. An account is needed, so exposure follows who can sign in: customers, partners or staff.
- Between one role or tenant and another. An attacker who crosses it can reach data or actions their role should not allow.
Questions to answer about your own systems
- Where does moyangzhan langchain4j-aideepin run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Read more
Patches and commits
Advisories
More reading
- github.com/moyangzhan/langchain4j-aideepin/blob/v3.30.0/server/adi-common/src/main/java/com/moyz/adi/common/service/CharacterService.java#L105-L125
- hackmd.io/@hieuPenguinnn/langchain4j-aideepin-character-conversation-cross-user-idor
- hackmd.io/@hieuPenguinnn/cve-2026-121938-langchain4j-aideepin-character-conversation-cross-user-idor
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.