External risk intelligence

Attackers can control accounts by injecting data into Flowise registration

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-41267

The vulnerability resides in the account registration endpoint of Flowise Cloud. Because this is a public-facing cloud service that supports user registration, the affected endpoint is accessible over the internet by design to facilitate new account creation.

Flowiseai Flowise

before 3.1.0

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

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical vulnerability in Flowise Cloud's account registration allows unauthenticated attackers to manipulate important ownership and access controls during user creation. This could disrupt trust and security in shared environments.

  • Attackers can inject server-managed data.
  • Affects multi-tenant organization access.
  • Publicly reachable registration endpoint.

Attack Path

How an attacker could exploit the issue

An unauthenticated attacker can abuse Flowise's account registration to inject malicious data into server-managed fields. This allows them to manipulate ownership, timestamps, and organization roles, potentially compromising a multi-tenant environment.

  • Attacker targets account registration endpoint.
  • Unauthenticated remote access is required.
  • Manipulation of ownership and roles is possible.

Live Threat

Current exploitation, exposure, and threat context

Attackers will likely target this vulnerability due to its critical severity and the absence of authentication requirements for exploitation. The improper mass assignment in the account registration endpoint allows for direct manipulation of sensitive ownership and organizational data, which can be attractive for account takeover or privilege escalation in multi-tenant environments. The fixed version is 3.1.0.

  • Unauthenticated exploitation path.
  • Critical impact on data integrity.
  • Affects Flowise Cloud registration.

Operational Fix

Recommended remediation, mitigation, and detection steps

Prioritize patching Flowise to version 3.1.0 or later immediately, as this critical vulnerability allows unauthenticated attackers to inject server-managed fields during account creation, potentially compromising multi-tenant environments. If immediate patching is not feasible, isolate affected services to prevent further exploitation and implement strict network access controls.

  • Patch Flowise to 3.1.0 or newer.
  • Isolate or take services offline.
  • Monitor for unauthorized account creations.

Supplementary metadata

Validate whether this threat affects your internet-facing exposure.

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.

Frequently asked questions

What is Flowise and what is it used for?

Flowise is a tool that provides a drag-and-drop interface to help users build custom large language model flows. It allows for the creation of unique AI workflows by visually connecting different components and settings.

What kind of vulnerability does CVE-2026-41267 represent in Flowise?

CVE-2026-41267 is an improper mass assignment vulnerability, also known as JSON injection. This weakness allows attackers to inject data into server-managed fields during account creation, potentially manipulating ownership and access controls.

How could an attacker exploit this Flowise vulnerability?

An attacker could exploit this by sending specially crafted data to the account registration endpoint. This allows them to inject server-managed fields and nested objects, thereby controlling ownership metadata, timestamps, and organization associations without needing any prior authentication.

Who should be concerned about this Flowise vulnerability?

Organizations using Flowise Cloud should be concerned. The Halo Surface Signal indicates this is very likely to be exploited because the vulnerability is in a public-facing cloud service's registration endpoint, making it accessible over the internet.

What is the first step to address this Flowise CVE?

The immediate first step is to update Flowise to version 3.1.0 or a later version. This update addresses the improper mass assignment vulnerability that allows for data injection during account creation.

References