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Flowise: Broken Access Control in Stripe Subscription Endpoints Allows Cross-Tenant Billing Manipulation

High severity GitHub Reviewed Published Jul 29, 2026 in FlowiseAI/Flowise • Updated Aug 4, 2026

Package

npm flowise (npm)

Affected versions

<= 3.1.2

Patched versions

3.1.3

Description

Summary

Several organization billing endpoints accept attacker-controlled Stripe identifiers (subscriptionId) without verifying that the identifier belongs to the authenticated user's organization. This allows an authenticated attacker to perform unauthorized Stripe subscription operations on other tenants. As a result, an authenticated user can manipulate the Stripe subscription of another organization by supplying a victim organization's subscriptionId.

This allows attackers to perform unauthorized billing operations such as changing subscription plans or modifying seat quantities, resulting in potential financial impact and service disruption.

Details

Multiple organization billing endpoints accept subscriptionId directly from user input without validating ownership. The server relies on a client-supplied Stripe subscription identifier rather than resolving the subscription from the authenticated user's organization context.

File

packages/server/src/enterprise/routes/organization.route.ts

Affected routes:

router.post('/update-additional-seats', organizationController.updateAdditionalSeats)
router.post('/update-subscription-plan', organizationController.updateSubscriptionPlan)
updateSubscriptionPlan

File

packages/server/src/enterprise/controllers/organization.controller.ts

public async updateSubscriptionPlan(req: Request, res: Response, next: NextFunction) {
    const { subscriptionId, newPlanId, prorationDate } = req.body

    const identityManager = getRunningExpressApp().identityManager

    const result = await identityManager.updateSubscriptionPlan(
        req,
        subscriptionId,
        newPlanId,
        prorationDate
    )

    return res.status(StatusCodes.OK).json(result)
}

The server trusts the user-supplied subscriptionId and forwards it to the Stripe integration layer.

Missing validation:
subscriptionId belongs to req.user.activeOrganization

updateAdditionalSeats

public async updateAdditionalSeats(req: Request, res: Response, next: NextFunction) {
    const { subscriptionId, quantity, prorationDate } = req.body

    const identityManager = getRunningExpressApp().identityManager

    const result = await identityManager.updateAdditionalSeats(
        subscriptionId,
        quantity,
        prorationDate
    )

    return res.status(StatusCodes.OK).json(result)
}

Again, the subscriptionId is taken directly from the request body without verifying ownership.

PoC

Step 1 - Obtain victim subscriptionId

This identifier may be obtained via the organization read endpoint or other exposed references.

Example:

sub_YYYYYYYYYYYY

Step 2 - Modify victim subscription

POST /api/v1/organization/update-subscription-plan
Host: target.example.com
Cookie: token=<attacker-session>
Content-Type: application/json

{
  "subscriptionId": "sub_YYYYYYYYYYYY",
  "newPlanId": "free_plan_id",
  "prorationDate": 1735689600
}

Step 3 - Change seat quantity

POST /api/v1/organization/update-additional-seats
Host: target.example.com
Cookie: token=<attacker-session>
Content-Type: application/json

{
  "subscriptionId": "sub_YYYYYYYYYYYY",
  "quantity": 0,
  "prorationDate": 1735689600
}

Impact

An authenticated attacker can manipulate the Stripe subscription of other organizations.

Possible consequences include:

  • Unauthorized subscription upgrades to higher-priced plans
  • Manipulation of paid seat quantities leading to unintended charges
  • Service disruption through plan downgrades

Because the vulnerability allows cross-tenant manipulation of billing resources, it represents a high-impact authorization flaw.

References

@igor-magun-wd igor-magun-wd published to FlowiseAI/Flowise Jul 29, 2026
Published to the GitHub Advisory Database Aug 4, 2026
Reviewed Aug 4, 2026
Last updated Aug 4, 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 None
User interaction None
Vulnerable System Impact Metrics
Confidentiality None
Integrity High
Availability Low
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:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

EPSS score

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.

CVE ID

CVE-2026-70476

GHSA ID

GHSA-gmmw-qg98-6j6p

Source code

Credits

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