highAgent ThreatFramework Vulnerability

IBM Langflow Improper Authentication Leading to Unauthorized Flow Execution

First seen Aug 29, 2026 · Updated Aug 29, 2026 · CVSS 8.2

langflowimproper-authenticationunauthenticated-accessagent-frameworkflow-executioninformation-disclosureASI02 · Tool MisuseSurface: PlannerPropagation: Single Hop

IBM Langflow OSS versions 1.0.0 through 1.11.1 contain an improper authentication flaw that allows a remote attacker to execute arbitrary flows and access sensitive information without valid credentials. This is a genuine, high-impact vulnerability in a widely used agent/LLM orchestration framework that could let attackers run arbitrary agent pipelines and exfiltrate data. Organizations running affected versions should patch immediately.

Technical Analysis

The vulnerability stems from insufficient authentication checks in Langflow's flow execution API or interface, allowing remote unauthenticated or under-privileged actors to invoke arbitrary flows that were meant to be access-controlled. Since Langflow flows can embed tool calls, credential access, and data connectors, an attacker exploiting this gap gains the ability to trigger arbitrary agent logic and read sensitive data exposed within flow configurations or outputs. The entry point is the improperly authenticated API/UI layer rather than a specific tool, but the impact crosses into the tool and data layer since flows often orchestrate external tool calls, API keys, and databases. This effectively grants an external attacker the same execution privileges as a legitimate flow operator, bypassing intended access boundaries.

Affected Systems

IBM Langflow OSS

Detection Signatures

  • Unauthenticated or anomalous requests to Langflow flow execution endpoints (e.g., /api/v1/run, /flows/*)
  • Requests missing expected session/auth tokens that still succeed
  • Unexpected flow executions in audit logs triggered by unknown or external IP addresses
  • Spikes in flow invocation from unrecognized user agents or missing user context
  • Access to flow configuration or output data without corresponding authenticated session

Remediation Steps

  1. 1

    Upgrade Langflow

    Update IBM Langflow OSS to a patched version beyond 1.11.1 that resolves the authentication flaw.

  2. 2

    Restrict network exposure

    Ensure Langflow instances are not directly exposed to the public internet; place behind VPN, firewall, or authenticated reverse proxy.

  3. 3

    Enforce strong authentication

    Verify all flow execution and management endpoints require valid session tokens or API keys, and audit for bypassable routes.

  4. 4

    Audit flow contents

    Review existing flows for embedded credentials, API keys, or sensitive data that could be exposed if unauthorized execution occurs.

  5. 5

    Enable logging and monitoring

    Turn on detailed access logging for flow execution endpoints and monitor for anomalous or unauthenticated invocation patterns.

CVE / Advisory IDs

CVE-2026-18891

Industries Most Exposed

TechnologySoftware DevelopmentFinancial ServicesHealthcareAny organization deploying Langflow for AI/agent orchestration

Sources

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