CVE-2026-73601

CRITICAL
Published August 13, 2026

Flowise versions before 3.1.3 contain a remote code execution vulnerability in the Custom MCP node when CUSTOM_MCP_PROTOCOL is set to stdio, allowing authenticated users to execute arbitrary commands by manipulating environment variables and command arguments. Attackers can abuse PYTHONWARNINGS and...

Full CISO analysis pending enrichment.

What systems are affected?

Package Ecosystem Vulnerable Range Patched
Flowise npm No patch

Do you use Flowise? You're affected.

How severe is it?

CVSS 3.1
N/A
EPSS
N/A
Exploitation Status
No known exploitation
Sophistication
N/A

What should I do?

No patch available

Monitor for updates. Consider compensating controls or temporary mitigations.

Which compliance frameworks are affected?

Compliance analysis pending. Sign in for full compliance mapping when available.

Frequently Asked Questions

What is CVE-2026-73601?

Flowise versions before 3.1.3 contain a remote code execution vulnerability in the Custom MCP node when CUSTOM_MCP_PROTOCOL is set to stdio, allowing authenticated users to execute arbitrary commands by manipulating environment variables and command arguments. Attackers can abuse PYTHONWARNINGS and BROWSER environment variables with python3, or leverage the root working directory with node to bypass validation and execute system commands.

Is CVE-2026-73601 actively exploited?

No confirmed active exploitation of CVE-2026-73601 has been reported, but organizations should still patch proactively.

How to fix CVE-2026-73601?

No patch is currently available. Monitor vendor advisories for updates.

What is the CVSS score for CVE-2026-73601?

No CVSS score has been assigned yet.

What are the technical details?

Original Advisory

Flowise versions before 3.1.3 contain a remote code execution vulnerability in the Custom MCP node when CUSTOM_MCP_PROTOCOL is set to stdio, allowing authenticated users to execute arbitrary commands by manipulating environment variables and command arguments. Attackers can abuse PYTHONWARNINGS and BROWSER environment variables with python3, or leverage the root working directory with node to bypass validation and execute system commands.

Weaknesses (CWE)

CWE-95 — Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection'): The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes code syntax before using the input in a dynamic evaluation call (e.g. "eval").

  • [Architecture and Design, Implementation] If possible, refactor your code so that it does not need to use eval() at all.
  • [Implementation] Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylis

Source: MITRE CWE corpus.

Timeline

Published
August 13, 2026
Last Modified
August 13, 2026
First Seen
August 13, 2026

Related Vulnerabilities