CVE-2026-81211

Remote auth attacker can run arbitrary Python via custom components in stored flows.

• CVSS 8.8
• 862
• Authentication, Authorization, and Session Management
• Remote

IBM Langflow OSS 1.0.0 through 1.11.5 could allow a remote authenticated attacker to execute arbitrary Python code due to improper authorization of custom components in stored flows.

CVE

CVE-2026-81211

CWE

862

CVSS base score

8.8

Published

2026-09-10

OWASP

A01 Broken Access Control

Orthogonal defect classification

Checking

Code defect classification

Missing Check

Category

Authentication, Authorization, and Session Management

Subcategory

Privilege Escalation

Accessibility scope

Remote

Impact

Arbitrary Code Execution

Affected component

Langflow

Fixed by upgrading

Yes

Solution

Upgrade IBM Langflow to version 1.11.6 or later, where the authorization issue for custom components in stored flows is fixed.

import json

def load_flow(flow_id: str, user):
    # VULNERABLE: exec of untrusted component code without auth check
    flow_data = json.loads(get_flow_json_from_db(flow_id))  # placeholder
    components = {}
    for comp in flow_data.get("components", []):
        code = comp["code"]
        exec(code, {}, components)  # loads component classes/functions
    return components

import json

def load_flow(flow_id: str, user):
    # FIX: restrict exec to privileged users only
    flow_data = json.loads(get_flow_json_from_db(flow_id))  # placeholder
    components = {}
    if not user.is_admin:
        raise PermissionError("Unauthorized component execution")
    for comp in flow_data.get("components", []):
        code = comp["code"]
        exec(code, {}, components)
    return components

__VAITP_MODEL_REFUSED__

@misc{vaitp:cve202681211,
  title        = {{Remote auth attacker can run arbitrary Python via custom components in stored flows.}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2026},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2026-81211},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2026-81211/}}
}