CVE-2026-70470 Flowise: Pyodide validator Unicode homoglyph bypass leads to RCE
Attackers can bypass Python code validation using Unicode homoglyphs to execute arbitrary code on the host via Pyodide interop.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-70470?
CVE-2026-70470 is a critical code injection vulnerability in Flowiseai Flowise, published on 4 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-184
Which versions are affected by CVE-2026-70470?
4 open source packages ship an affected version, including flowise and flowise-components. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
flowise npm | All versions | 3.1.3 |
flowise npm | All versions | 3.1.3 |
flowise-components npm | All versions | 3.1.3 |
flowise-components npm | All versions | 3.1.3 |
Products include Flowiseai Flowise.
How do I fix CVE-2026-70470?
Upgrade flowise to 3.1.3 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-70470 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-70470 exists.
Other vulnerabilities in Flowiseai Flowise
- CVE-2025-71338 Flowise through 2.2.7 - Arbitrary File Write to Remote Code Execution via document-store API
- CVE-2026-40933 Flowise: Authenticated RCE Via MCP Adapters
- CVE-2025-61913 Flowise is vulnerable to arbitrary file read, arbitrary file write
- CVE-2025-59528 Flowise has Remote Code Execution vulnerability
- CVE-2026-52098 Code injection in n/a
Sources
Also known as GHSA-52fh-8v99-63c2.