External risk intelligence

Flowise OAuth2 Credential Refresh Unauthorized Access

CVE advisorySeverity: CRITICAL (CVSS 9.2)

CVE-2026-70478

Flowise is a web-based application designed for building LLM flows and interfaces. It typically operates as a web service or API endpoint. Because it provides a user interface and API for external integrations, it is commonly deployed in a network-accessible manner, making this endpoint a likely target for remote interaction.

Information Disclosure

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 concerns a vulnerability in Flowise, a tool used for building custom large language model flows. The issue lies in an unauthenticated API endpoint that, when exploited, could allow an attacker to access user credentials for connected services and potentially exhaust refresh token quotas, impacting the availability and security of those integrated services. The main concern is confirming relevance and exposure.

Unauthenticated API access compromises credentials.
Compromised credentials expose connected services.
Confirm relevance and assess exposure.

Attack Path

How an attacker could exploit the issue

An attacker could target a Flowise instance that is accessible over the network. By sending a specific request to an unauthenticated API endpoint, an attacker can access stored credentials. This could allow them to impersonate a user and access connected services, potentially leading to unauthorized actions or the exhaustion of refresh token quotas.

No authentication required for endpoint.
Attacker calls refresh credential API.
Risk of unauthorized access and quota exhaustion.

Live Threat

Current exploitation, exposure, and threat context

When supported by the advisory, an unauthenticated attacker could access and decrypt stored credentials. This could allow them to refresh access tokens for a victim's connected service and potentially exhaust refresh-token quotas.

Stored OAuth credentials and connected service access.
Via unauthenticated API endpoint access.
Unauthorized access to victim's connected services.

Operational Fix

Recommended remediation, mitigation, and detection steps

Platform teams responsible for deploying and managing Flowise instances should prioritize confirming the reachability and business criticality of affected endpoints. The first practical step involves identifying all deployed Flowise instances, assessing their exposure to external networks, and then determining the accountable owner for each instance to plan a risk-based remediation strategy.

Platform teams own the issue.
Verify endpoint reachability and business impact.
Plan remediation based on risk assessment.

Supplementary metadata

CVSS vector

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Frequently asked questions

What is Flowise?

Flowise is a software platform with a visual, drag-and-drop interface used to design and automate workflows involving large language models (LLMs). Developers and teams use it to connect LLMs to various external services and data sources, essentially acting as an orchestration layer that manages API interactions and credential handling for these integrated AI-powered applications.

How does CVE-2026-70478 represent a security weakness?

This vulnerability is classified as CWE-200, which concerns the exposure of sensitive information. In this specific case, the flaw allows unauthorized parties to access an API endpoint that was intended to be protected. By communicating with this endpoint, an attacker can retrieve decrypted credentials and gain the ability to impersonate a user's connection to third-party OAuth services.

Do I need special access to trigger the CVE-2026-70478 flaw?

No. The vulnerability exists because the specific API endpoint does not require any authentication or login credentials to function. An attacker only needs the ability to send a network request to the target system. Simply accessing a valid, yet known, credential ID is sufficient to interact with the vulnerable process; standard interactions that do not target this specific endpoint will not trigger the issue.

Why is this Flowise issue a priority?

Halo Surface Signal indicates that because Flowise functions as a web-based service with external API integrations, it is often deployed in network-accessible environments. This visibility makes it a likely target for remote interaction. If your instance is reachable over the internet, an attacker can exploit the endpoint to access your integrated services without needing to bypass any initial security hurdles.

How do I respond to this vulnerability?

The most effective way to secure your environment is to update Flowise to version 3.1.3 or later, which resolves the unauthenticated access issue. Before applying the update, identify all Flowise instances within your infrastructure, assess their network exposure, and determine which instances handle critical business integrations to prioritize your patching efforts accordingly.

References

github.com/FlowiseAI/Flowise/security/advisories/GHSA-qgvm-j2hm-…

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.