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FlowiseAI has Mass Assignment in Tool Update Endpoint that Allows Cross-Workspace Resource Reassignment

High severity GitHub Reviewed Published May 14, 2026 in FlowiseAI/Flowise • Updated Jun 9, 2026

Package

npm flowise (npm)

Affected versions

<= 3.1.1

Patched versions

3.1.2

Description

Summary

A Mass Assignment vulnerability exists in the tool update endpoint of FlowiseAI.

The endpoint allows authenticated users to modify server-controlled properties such as workspaceId, createdDate, and updatedDate when updating a tool resource.

Due to missing server-side validation and authorization checks, an attacker can manipulate the workspaceId field and reassign tools to arbitrary workspaces. This breaks tenant isolation in multi-workspace environments.

Details

The endpoint responsible for updating tools:

PUT /api/v1/tools/{toolId}

accepts a JSON request body containing tool metadata.

However, the server does not restrict which properties may be modified by the client. As a result, user-controlled request bodies can include additional fields that should normally be controlled only by the backend.

Server-controlled fields that can be manipulated include:

  1. workspaceId
  2. createdDate
  3. updatedDate

The request body is directly merged into the underlying database entity without proper DTO validation or authorization checks.

PoC

Authenticate to the Flowise interface.

Capture the request used to update a tool:

PUT /api/v1/tools/<TOOL_ID>
Content-Type: application/json

Modify the request body by injecting additional fields:

{
  "name": "aaa",
  "description": "bbb",
  "color": "linear-gradient(rgb(109,215,45), rgb(136,170,134))",
  "schema": "[]",
  "func": "",
  "iconSrc": "test",
  "workspaceId": "11111111-2222-3333-4444-555555555555",
  "createdDate": "1995-03-06T14:17:50.000Z",
  "updatedDate": "1995-03-06T14:17:50.000Z"
}

Send the request.

Observe that the response includes the manipulated fields:

{
  "workspaceId": "11111111-2222-3333-4444-555555555555",
  "createdDate": "1995-03-06T14:17:50.000Z"
}

This confirms that client-controlled values are accepted and persisted by the server.

Impact

This vulnerability allows authenticated users to manipulate internal attributes of tool resources.

Confirmed impacts include:

  • Cross-workspace reassignment of tools (workspaceId)
  • Unauthorized modification of metadata (createdDate, updatedDate)

In multi-tenant deployments, this may allow an attacker to move tools between workspaces without authorization, breaking tenant isolation boundaries.

References

@igor-magun-wd igor-magun-wd published to FlowiseAI/Flowise May 14, 2026
Published to the GitHub Advisory Database May 14, 2026
Reviewed May 14, 2026
Published by the National Vulnerability Database Jun 8, 2026
Last updated Jun 9, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity High
Attack Requirements None
Privileges Required Low
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability None
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(18th percentile)

Weaknesses

Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. Learn more on MITRE.

Authorization Bypass Through User-Controlled Key

The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. Learn more on MITRE.

Improperly Controlled Modification of Dynamically-Determined Object Attributes

The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified. Learn more on MITRE.

CVE ID

CVE-2026-42862

GHSA ID

GHSA-x5v6-pj28-cwwm

Source code

Credits

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