Orgs at Risk: LangChat Flaw Exposes Passwords, Grants Unauthenticated Super-Admin Access

LangChat contains a critical vulnerability that permits remote attackers to access internal application functions without any form of authentication. This means anyone on the internet can interact with the system’s core controls as if they had valid credentials, posing a severe risk to any organisation using the software.

According to the National Vulnerability Database record, the flaw exists in versions of LangChat up to commit 2a6285a. The root cause is a missing Sa-Token interceptor, which fails to enforce security checks on REST controllers. This omission allows unauthenticated remote attackers to bypass standard login requirements entirely.

What we know

The National Vulnerability Database rates CVE-2026-111704 as critical, assigning it a CVSS score of 9.3. The weakness is classified under CWE-306, which relates to missing authentication for critical functionality. The vulnerability affects the software through commit 2a6285a, meaning any deployment using this or earlier code is exposed.

Exploiting this flaw does not require prior access or credentials. An attacker can send specific requests to the server to trigger the vulnerability. The NVD description states that this allows remote attackers to access REST controllers because no Sa-Token interceptor is registered to validate the incoming requests.

The consequences of this access are extensive. Attackers can query the endpoint /api/v1/auth/users to read passwords in plaintext. They can also retrieve API keys for large language model providers, which could lead to significant financial costs if abused.

Furthermore, the vulnerability allows attackers to modify or delete existing data within the system. Perhaps most dangerously, they can create new super-admin accounts. This grants them persistent, high-level control over the LangChat instance, allowing further manipulation of the application long after the initial attack.

Defender's checklist

• Identify all systems running LangChat and check their current version or commit hash against the affected range.
• Verify whether the Sa-Token interceptor is correctly registered in your application configuration files.
• Monitor server logs for unusual requests to the /api/v1/auth/users endpoint from unknown IP addresses.
• Audit user accounts for any newly created super-admin roles that were not authorised by internal staff.

The background in plain language

Authentication is the process of verifying who a user is, usually through a username and password. In secure software, every request to sensitive parts of the system must be checked against a list of allowed users. When this check is missing or broken, the system treats every visitor as a trusted user. This is known as a missing authentication vulnerability. It is particularly dangerous because it allows attackers to perform administrative tasks, view private data, and change system settings without needing to steal or guess any credentials first.

Background: Large language models

Large language models are zero-shot reasoners only in appearance. They predict the next word by matching patterns in training data, not by applying logical rules. This means they can solve novel problems if similar examples exist in their data, but they fail when true novel logic is required.

Read the full guide: Are Large Language Models Zero-Shot Reasoners? The Reality Check

What to do and how to stay safe: LangChat

• Isolate affected LangChat instances from public internet access until a secure configuration or update is applied.
• Review access logs for signs of unauthenticated requests to administrative endpoints or user data routes.
• Implement strict firewall rules to block external access to internal API endpoints if they do not require public exposure.
• Monitor for unexpected changes to user permissions or the creation of new administrative accounts.

Step-by-step guide: Virtual Patching: Benefits, Limits and When to Use It

General security guidance from the TechWire Beat newsroom. It is not confirmed advice from the organisations named in this story.

Frequently asked questions

What is CVE-2026-111704?

It is a critical missing authentication vulnerability in LangChat that allows unauthenticated remote attackers to access REST controllers and sensitive data.

Which versions of LangChat are affected?

According to the NVD record, LangChat through commit 2a6285a is affected by this vulnerability.

Can attackers steal API keys with this flaw?

Yes, the vulnerability allows attackers to retrieve LLM provider API keys and read plaintext passwords by querying specific endpoints.