---
title: "CVE-2026-70470: Flowise: Pyodide validator Unicode homoglyph bypass leads to RCE"
url: https://erroneo.us/security/cve/CVE-2026-70470/
description: "CVE-2026-70470 (flowise (npm)): Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.3, Flowise…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-08-04
date_modified: 2026-08-04
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-70470"
kev: false
cvss: 9.5
epss: 0.00972
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-70470: Flowise: Pyodide validator Unicode homoglyph bypass leads to RCE

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 1.0% , percentile 62: FIRST’s model estimates a 1.0% chance of exploitation activity in the next 30 days, higher than 62% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes flowise (npm) <= 3.1.2, fixed in 3.1.3 ; flowise-components (npm) <= 3.1.2, fixed in 3.1.3 . Check your lockfile, including transitive dependencies.

## What it is

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.3, Flowise validatePythonCodeForDataFrame 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 js module interop. The validator gates pyodide.runPythonAsync in packages/components/nodes/agents/CSVAgent/CSVAgent.ts and packages/components/nodes/agents/AirtableAgent/AirtableAgent.ts with an ASCII word-boundary blacklist. JavaScript regex word boundaries are ASCII-only, while Python 3 NFKC-normalizes identifiers at parse time, so homoglyph forms such as cl𝐚ss, subcl𝐚sses, b𝐚se, and b𝐮iltins bypass the blacklist and are parsed as their ASCII equivalents. This issue is fixed in version 3.1.3.

## Affected packages

- npm `flowise` <= 3.1.2 → fixed: 3.1.3
- npm `flowise-components` <= 3.1.2 → fixed: 3.1.3

## Affected products (CVE record)

- FlowiseAI Flowise: < 3.1.3

## Severity

- GitHub_M CVSS 4.0: 9.5 `CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`
- GitHub CVSS 4.0: 9.5 `CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.97% probability of exploitation activity in the next 30 days; percentile 62.

## Sources

- [GitHub Advisory GHSA-52fh-8v99-63c2](https://github.com/advisories/GHSA-52fh-8v99-63c2)
- [CVE.org record CVE-2026-70470](https://www.cve.org/CVERecord?id=CVE-2026-70470)
- [NVD entry CVE-2026-70470](https://nvd.nist.gov/vuln/detail/CVE-2026-70470)
- [github.com](https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-52fh-8v99-63c2)
- [github.com](https://github.com/FlowiseAI/Flowise/pull/6499)
- [github.com](https://github.com/FlowiseAI/Flowise/commit/f4e2794f6a576b94578f2fdafbf49c2fb304626c)
- [github.com](https://github.com/FlowiseAI/Flowise/releases/tag/flowise@3.1.3)

---
Source page: https://erroneo.us/security/cve/CVE-2026-70470/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt