Flowise: Improper Mass Assignment in Account Registration Enables Unauthorized Organization Association

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.0, an improper mass assignment (JSON injection) vulnerability in the account registration endpoint of Flowise Cloud allows unauthenticated attackers to inject server-managed fields and nested objects during account creation. This enables client-controlled manipulation of ownership metadata, timestamps, organization association, and role mappings, breaking trust boundaries in a multi-tenant environment. This vulnerability is fixed in 3.1.0.

Source published

23 Apr 2026 19:12:26 UTC

Source modified

23 Apr 2026 19:44:53 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.0, an improper mass assignment (JSON injection) vulnerability in the account registration endpoint of Flowise Cloud allows unauthenticated attackers to inject server-managed fields and nested objects during account creation. This enables client-controlled manipulation of ownership metadata, timestamps, organization association, and role mappings, breaking trust boundaries in a multi-tenant environment. This vulnerability is fixed in 3.1.0.

Source published

Apr 23, 2026, 7:12:26 PM (timezone not stated)

Source modified

Apr 23, 2026, 7:44:53 PM (timezone not stated)

Observed here

28 Oct 2026 05:07:30 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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EUVD CVSS 3.1 · 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.0, an improper mass assignment (JSON injection) vulnerability in the account registration endpoint of Flowise Cloud allows unauthenticated attackers to inject server-managed fields and nested objects during account creation. This enables client-controlled manipulation of ownership metadata, timestamps, organization association, and role mappings, breaking trust boundaries in a multi-tenant environment. This vulnerability is fixed in 3.1.0.

Source published

23 Apr 2026 20:16:15 UTC

Source modified

26 Oct 2026 21:10:00 UTC

Observed here

27 Oct 2026 10:10:07 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS 3.1 · [email protected] · Primary · 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

### Summary An improper mass assignment (JSON injection) vulnerability in the account registration endpoint of Flowise Cloud allows unauthenticated attackers to inject server-managed fields and nested objects during account creation. This enables client-controlled manipulation of ownership metadata, timestamps, organization association, and role mappings, breaking trust boundaries in a multi-tenant environment. ### Details The POST /api/v1/account/register endpoint is intended to accept a minimal payload to create a new user account (e.g., name, email, password). However, the backend fails to enforce a strict allowlist or DTO-based validation and instead blindly maps client-supplied JSON to internal domain models. As a result, attackers can include additional nested objects and server-managed fields in the request body such as organization, organizationUser, workspace, workspaceUser, and metadata fields like createdBy, updatedBy, createdDate, and updatedDate. These fields are persisted as provided by the client rather than being generated or validated server-side. This behavior demonstrates a trust boundary violation where authorization and ownership decisions that must be enforced by the server are effectively delegated to untrusted client input. In a multi-tenant SaaS context, this can lead to unauthorized organization association and role assignment during registration. ### PoC Send a standard registration request: ```http POST /api/v1/account/register HTTP/2 Host: cloud.flowiseai.com Content-Type: application/json { "user": { "name": "Test User", "email": "[email protected]", "credential": "StrongPassword123!" } } ``` Observe the 201 Created response returning a newly created user and related objects (organization, workspace, roles). Send a modified registration request that injects additional server-managed fields and nested objects: POST /api/v1/account/register HTTP/2 Host: cloud.flowiseai.com Content-Type: application/json ```http { "user": { "name": "Injected User", "email": "[email protected]", "credential": "StrongPassword123!", "createdBy": "<arbitrary-uuid>", "updatedBy": "<arbitrary-uuid>", "createdDate": "1999-12-27T13:10:47.666Z", "updatedDate": "1999-12-27T13:10:47.666Z" }, "organization": { "id": "<existing-organization-uuid>", "name": "Injected Organization" }, "organizationUser": { "organizationId": "<existing-organization-uuid>", "roleId": "<owner-role-uuid>" } } ``` Observe that the server responds with 201 Created and persists the injected fields, reflecting client-controlled values for ownership metadata, timestamps, and organization association. ### Impact - Vulnerability Class: Mass Assignment / JSON Injection / Improper Input Validation. - Who is impacted: All deployments of Flowise Cloud exposing the registration endpoint. By supplying a known organizationId during registration, an unauthenticated attacker can create a new user account directly associated with an existing organization they do not belong to. This results in unauthorized cross-tenant access and privilege escalation at account creation time, completely bypassing organizational ownership and trust boundaries. **Security Consequences**: 1. Client-controlled manipulation of server-managed fields (audit timestamps, ownership metadata). 2. Unauthorized association of newly created accounts with existing organizations. 3. Injection of role and membership relationships during registration. 4. Violation of trust boundaries in a multi-tenant environment, increasing the risk of privilege abuse and audit integrity failures.

Source published

16 Apr 2026 21:44:24 UTC

Source modified

5 May 2026 16:11:36 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Publisher rating · HIGH