External risk intelligence

LangChat Missing Authentication Exposes Credentials and Admin Access

CVE advisorySeverity: CRITICAL (CVSS 9.3)

CVE-2026-111704

The vulnerability exists in REST API controllers designed to handle authentication and user management tasks. Applications providing these services are commonly deployed as internet-facing APIs to support web or mobile interfaces. Given the nature of the software as a chat and LLM provider platform, it is typically intended for external network reachability to function in its primary role.

Missing Authentication

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This advisory addresses a vulnerability in LangChat affecting its authentication mechanisms. The issue allows unauthorized remote access to sensitive system functions, potentially exposing user credentials, API keys, and enabling unauthorized account creation or data manipulation. The main concern is confirming relevance and exposure of this technology within the organization.

Unauthenticated access to sensitive data and controls.
Potential compromise of user accounts and API keys.
Assess relevance and exposure to our systems.

Attack Path

How an attacker could exploit the issue

An attacker can reach this vulnerability through the network without needing any credentials. By sending requests to specific API endpoints, they can interact with unprotected REST controllers. This interaction allows them to perform sensitive actions, such as reading user passwords and API keys, or altering and deleting data within the application.

No authentication required for access.
Triggered by querying unprotected API endpoints.
High risk of data exposure and modification.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability in LangChat could allow unauthenticated attackers to access sensitive user and system information. When supported by the advisory, attackers could query API endpoints to read plaintext passwords, retrieve LLM provider API keys, and modify or delete data.

User credentials and LLM keys could be exposed.
Attackers may query unauthenticated REST controllers.
Unauthorized data modification or deletion is possible.

Operational Fix

Recommended remediation, mitigation, and detection steps

Teams responsible for managing the LangChat application and its underlying infrastructure should prioritize identifying all instances of the affected technology. Given the vulnerability's potential to expose sensitive data and allow unauthorized account modifications, confirming reachability and business criticality is essential for risk-based remediation planning. Once confirmed, engaging the accountable application or platform owner will be the first practical step to initiating remediation efforts.

Own the vulnerability and remediation efforts.
Verify external access and business criticality.
Plan and coordinate remediation activities.

Supplementary metadata

CVSS vector

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Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is LangChat software?

LangChat is a platform designed to facilitate interactions with Large Language Models (LLMs). It acts as a bridge, managing user sessions and LLM provider connectivity. The software incorporates modules to handle authentication, user administration, and backend API services, which typically communicate via REST controllers to support connected web or mobile application interfaces.

What does CVE-2026-111704 mean for security?

This vulnerability is classified as CWE-306, which refers to a missing authentication weakness. In plain terms, the software fails to verify the identity of anyone making requests to its REST API controllers. Because these endpoints lack the required interceptors to block unauthorized traffic, someone can interact with them as if they were a trusted administrator, gaining full access to internal system functions.

How do attackers trigger this vulnerability?

An attacker triggers this flaw by sending standard network requests directly to specific API endpoints, such as the user management paths, without providing any credentials. The vulnerability exists specifically because the software lacks a registered security interceptor. It is important to note that actions performed within authenticated sessions are not required; the bug specifically affects paths that should be protected but remain open to any remote connection.

Is my instance of LangChat at risk?

Halo Surface Signal indicates a high likelihood of risk if your deployment is internet-facing. Because this software is designed to function as an API backend for chat services, it is often exposed to the network to serve its intended purpose. If your instance is reachable from the internet, it is susceptible to these unauthorized remote requests, potentially leading to the compromise of stored passwords and LLM keys.

What should I do if I run LangChat?

First, identify every location where LangChat is deployed within your infrastructure to assess if it is reachable externally. Once you have a clear inventory, determine the business criticality of those specific instances. Your primary practical step is to coordinate with the application owners or internal developers to confirm the presence of this vulnerability and plan for the necessary security updates or configuration changes.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.