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CVE-2026-70470 critical CVSS 9.8

Vulnerability in flowise (CVE-2026-70470)

Summary

Vulnerability in flowise (CVE-2026-70470). Successful exploitation can lead to full system takeover. Exploitable via POST /api/v1/prediction/{chatflowId}. Mitigation: upgrade to 3.1.3 or later.

Original description

The description as published by the source.

Summary

The validatePythonCodeForDataFrame blacklist in packages/components/src/pythonCodeValidator.ts can be bypassed with Unicode homoglyph identifiers, allowing arbitrary Python execution inside Pyodide and full OS command execution on the Flowise host via Pyodide's js module interop. This reopens the RCE paths patched as GHSA-3hjv-c53m-58jj (CSV Agent) and GHSA-v38x-c887-992f (Airtable Agent).

Details

packages/components/src/pythonCodeValidator.ts gates every call to pyodide.runPythonAsync in packages/components/nodes/agents/CSVAgent/CSVAgent.ts (lines 147, 198) and packages/components/nodes/agents/AirtableAgent/AirtableAgent.ts (line 186). The gate is a regex blacklist:

{ pattern: /\bimport\b/g, ... },
{ pattern: /\b__class__\b/g, ... },
{ pattern: /\b__subclasses__\s*\(/g, ... },
{ pattern: /\b__builtins__\b/g, ... },
{ pattern: /\b__mro__\b/g, ... },
// ... about 30 similar rules

Two design flaws combine into a bypass:

  1. JavaScript regex \b is ASCII-only. Word boundaries are computed against the ASCII word class [A-Za-z0-9_]. A Unicode letter such as U+1D41A (mathematical bold small a) is treated as a non-word character, so \b__class__\b never matches __cl𝐚ss__.
  2. Python 3 (PEP 3131) NFKC-normalizes every identifier at parse time. __cl𝐚ss__, __subcl𝐚sses__, __b𝐚se__, __b𝐮iltins__, and similar homoglyph forms are all parsed as their ASCII equivalents.

Attribute access obj.__cl𝐚ss__ is normalized because attribute names are iden…

Source: GitHub Security Advisories (Global) 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-2026-70470 has been found in flowise.
Attackers can target a specific entry point like POST /api/v1/prediction/{chatflowId} over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
What to do: upgrade flowise to 3.1.3 or later.
If unsure, ask your IT team or search "flowise CVE-2026-70470" on the vendor's site.

CVE-2026-70470 (flowise) — CWE-184 / CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: POST /api/v1/prediction/{chatflowId} / customReadCSV / pythonCode / pyodide.runPythonAsync
Patched: 3.1.3 — 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-184) exists in flowise. Attackers reach the vulnerable code path via POST /api/v1/prediction/{chatflowId} without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of flowise. Attack surface: POST /api/v1/prediction/{chatflowId} / customReadCSV / pythonCode / pyodide.runPythonAsync.

🔥 Severity

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

🔧 How to fix

Update to 3.1.3.

🛡️ 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 POST /api/v1/prediction/{chatflowId} requests with malformed payloads or SQL meta-characters. Run grep -r 'flowise' . 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 'flowise' . | 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 flowise 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
    Hunt for indicators of compromise detect 
    grep 'POST /api/v1/prediction/{chatflowId}' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで POST /api/v1/prediction/{chatflowId} への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。

  3. 3
    Apply patch patch 
    Upgrade flowise to 3.1.3

    ステージング環境で 3.1.3 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と、Step 2 で見つけた異常検知の続報チェックを含めること。

  4. 4
    Post-deployment verification verify 
    Replay attack against POST /api/v1/prediction/{chatflowId} on staging to confirm patch closes the vector

    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 Step 2 と同じログクエリでアラート再発が無いか継続監視。

Affected packages

npm flowise
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.1.3"}]}]
npm flowise-components
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.1.3"}]}]

References

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