Flowise: Improper Neutralization of Directives in Dynamically Evaluated Code
CVE-2026-73601 is a high-severity improper neutralization of directives in dynamically evaluated code vulnerability in Flowise from FlowiseAI, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 3.1.3 as the first without the flaw, so updating Flowise to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.1% chance of exploitation within 30 days, higher than 66% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Flowise to 3.1.3 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.0 | Critical | CNA (vulncheck.com) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Directives in Dynamically Evaluated Code
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).
How developers prevent this class of flaw
- If possible, refactor your code so that it does not need to use eval() at all.
- For Python programs, it is frequently encouraged to use the ast.literal_eval() function instead of eval, since it is intentionally designed to avoid executing code. However, an adversary could still cause excessive memory or stack consumption via deeply nested structures, so the python documentation discourages use of ast.literal_eval() on untrusted data.
More Improper Neutralization of Directives in Dynamically Evaluated Code vulnerabilities (CWE-95)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- vulncheck.com/advisories/flowise-before-remote-code-execution-via-custom-mcpThird Party Advisory
Other vulnerabilities in Flowise
- 8.5 High severity
- 8.5 High severity
- 7.5 High severity
- 8.3 High severity
- 7.7 High severity
- 7.7 High severity
Recent Improper Neutralization of Directives in Dynamically Evaluated Code vulnerabilities
- 9.9 Critical severity
- 7.8 High severity
- 9.3 Critical severity
- 8.8 High severity
- 8.8 High severity
- 9.6 Critical severity
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