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CVE-2026-8505 critical CVSS 9.8

Vulnerability in langflow (CVE-2026-8505)

Summary

Vulnerability in langflow (CVE-2026-8505). Successful exploitation can lead to full system takeover. Exploitable via WEBHOOK_AUTH_ENABLE. Mitigation: upgrade to 1.9.1 or later.

Original description

The description as published by the source.

Summary

A vulnerability in Langflow's webhook authentication logic allows unauthenticated users to trigger the execution of any flow. The system incorrectly bypasses API key validation when the WEBHOOK_AUTH_ENABLE configuration is set to False. This allows a remote attacker who knows a flow's UUID to execute it as if they were the owner, potentially leading to Remote Code Execution (RCE) or Denial of Service (DoS).

Details

The WEBHOOK_AUTH_ENABLE setting was introduced in v1.7.0 (#9139) with a default of False. The root cause is in the webhook authentication path, AuthService.get_webhook_user (src/backend/base/langflow/services/auth/service.py; the thin wrapper in src/backend/base/langflow/services/auth/utils.py just delegates to it):

async def get_webhook_user(self, flow_id: str, request: Request) -> UserRead:
    settings_service = self.settings
    ...
    # VULNERABILITY: If this setting is False (default in <= 1.9.0), it returns
    # the flow owner WITHOUT checking the API Key in the request.
    if not settings_service.auth_settings.WEBHOOK_AUTH_ENABLE:
        try:
            flow_owner = await get_user_by_flow_id_or_endpoint_name(flow_id)
            return flow_owner

By default (v1.7.0 through v1.9.0), Langflow treats WEBHOOK_AUTH_ENABLE as False, meaning all webhook endpoints are public. This relies exclusively on the secrecy of the flow_id (UUID), which is an insecure practice (Security by Obscurity).

A related report…

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-8505 has been found in langflow.
Attackers can target a specific entry point like WEBHOOK_AUTH_ENABLE over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
What to do: upgrade langflow to 1.9.1 or later.
If unsure, ask your IT team or search "langflow CVE-2026-8505" on the vendor's site.

CVE-2026-8505 (langflow) — CWE-306 / CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: WEBHOOK_AUTH_ENABLE / False / AuthService.get_webhook_user / flow_id
Patched: 1.9.1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-306) exists in langflow. Attackers reach the vulnerable code path via WEBHOOK_AUTH_ENABLE without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of langflow. Attack surface: WEBHOOK_AUTH_ENABLE / False / AuthService.get_webhook_user / flow_id.

🔥 Severity

Severity: Critical (CVSS 9.8/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 1.9.1.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'langflow' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'langflow' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で langflow を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade langflow to 1.9.1

    ステージング環境で 1.9.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

pip langflow
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.1"}]}]

References

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