Authenticated code execution via case-insensitive environment names
Published Jun 28, 2026 · Updated Jun 28, 2026
Improper case handling in Flowise before 3.1.3 allows remote authenticated users to execute code through Custom MCP stdio on Windows. The environment validator compares supplied names to a case-sensitive denylist, so node_options evades the NODE_OPTIONS entry but is honored by Windows and passed to a spawned process. Exploitation requires access to configure a Custom MCP stdio node and a command that starts Node.js, where --require loads attacker-selected JavaScript in the server context.
Summary
What happened
Improper case handling in Flowise before 3.1.3 allows remote authenticated users to execute code through Custom MCP stdio on Windows. The environment validator compares supplied names to a case-sensitive denylist, so node_options evades the NODE_OPTIONS entry but is honored by Windows and passed to a spawned process. Exploitation requires access to configure a Custom MCP stdio node and a command that starts Node.js, where --require loads attacker-selected JavaScript in the server context.
The record
- CVE
- CVE-2026-58057
- Published
- Jun 28, 2026
- Updated
- Jun 28, 2026
- Vendor
- FlowiseAI
- Product
- Flowise
- Classifications
- CWE-178, T1059.007
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 28, 2026CVE publishedPublication date reported by the CVE source.
- Jun 28, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <3.1.3
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- Flowise 3.1.2 Custom MCP Environment Variable Case Bypass PoCproof of concept · validated
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Technologies
Your stack
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Your stack
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