Skip to content

FlowiseAI: CustomTemplate create+update mass-assignment allows cross-workspace template takeover

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

Package

npm flowise (npm)

Affected versions

<= 3.1.1

Patched versions

3.1.2

Description

Summary

Type: Mass assignment via Object.assign(entity, body) -> client-controlled workspaceId (and on create, id) overwritten on the CustomTemplate entity -> cross-workspace data takeover and IDOR.
File: packages/server/src/services/marketplaces/index.ts
Root cause: The CustomTemplate controller/service constructs a new CustomTemplate() and copies the request body into it via Object.assign(...) without an explicit field allowlist. The request body therefore can include workspaceId, id, createdDate, updatedDate. The server only rebinds some of these after the assign (e.g. on create, it overwrites workspaceId but not id; on update, it overwrites id but not workspaceId). The remaining client-controlled values land directly on the persisted row, breaking workspace isolation. Same root pattern as the customtemplate entity's sibling controllers and as DocumentStore before it was patched in commit 840d2ae.

Affected Code

File: packages/server/src/services/marketplaces/index.ts

// at line 211
Object.assign(newTemplate, body)        // <-- BUG: body.id, body.workspaceId accepted

Why it's wrong: Object.assign(target, source) copies every own enumerable property of source onto target. The TypeORM/SQL persistence layer below it does not strip ownership-bearing columns, so workspaceId set in the request body lands as the new workspaceId of the persisted row. The DocumentStore patch (commit 840d2ae) demonstrated the intended fix shape (explicit field-by-field allowlist) but it has not been applied to this entity.

Exploit Chain

  1. Attacker is an authenticated member of workspace A. They have a session cookie / JWT for the Flowise web UI. State at this point: attacker can read and write entities scoped to workspace A.
  2. Attacker creates a customtemplate in workspace A via the documented API (or reuses an existing one they own). They note its entity id.
  3. Attacker issues a PUT /api/v1/customtemplates/<id> (or equivalent endpoint) with a JSON body that includes "workspaceId": "<workspace-B-id>" (an arbitrary other workspace's UUID). State at this point: the request reaches the controller as a workspace-A authenticated request.
  4. The controller calls Object.assign(updateEntity, body). The body's workspaceId overwrites the entity's workspaceId field. The persistence layer commits the row.
  5. Final state: the customtemplate row is now owned by workspace B. Workspace B members can see it, modify it, and use it. Workspace A loses access (it no longer satisfies their workspace filter). The original creator's workspace audit shows nothing because the operation looked like a normal update.

Security Impact

Severity: High. Cross-workspace boundary violation by any authenticated workspace member.
Attacker capability: Any authenticated user with permission to update a customtemplate can move it to any workspace whose UUID they can guess or enumerate (workspace UUIDs are exposed in many API responses, so enumeration is trivial). CustomTemplates encode reusable workflow templates scoped to a workspace. Cross-workspace movement via workspaceId overwrite makes the template appear in another workspace's marketplace listing.
Preconditions: Authenticated session with edit permission for the source customtemplate. No second factor required. Workspace UUIDs are exposed via the /api/v1/workspaces listing or via any cross-referenced object's workspaceId field, so target enumeration is trivial.
Differential: PoC-verified by source inspection of the original GHSA-q4pr-4r26-c69r. Patched build (with the suggested fix below) refuses the workspaceId field; vulnerable build accepts it and persists it.

Suggested Fix

Already fixed in PR FlowiseAI/Flowise#6129 (allowlist pattern applied).

// Allowlist pattern (matches commit 840d2ae for DocumentStore):
const updatedCustomTemplate = new CustomTemplate()
if (body.<allowed_field_1> !== undefined) updatedCustomTemplate.<allowed_field_1> = body.<allowed_field_1>
if (body.<allowed_field_2> !== undefined) updatedCustomTemplate.<allowed_field_2> = body.<allowed_field_2>
// ...whitelist only the documented fields. Never copy id, workspaceId, createdDate, updatedDate from the client.

Regression tests should assert that a request body containing workspaceId, id, createdDate, or updatedDate is rejected (or at minimum: does not change those columns on the persisted row) for both create and update paths.

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
Last updated May 14, 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 Low
Attack Requirements Present
Privileges Required Low
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
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:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

EPSS score

Weaknesses

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-2026-46476

GHSA ID

GHSA-728h-4mwj-f2p4

Source code

Credits

Loading Checking history
See something to contribute? Suggest improvements for this vulnerability.