Medium 5.0Published Jun 27, 2026

CVE-2026-58057Flowise - Custom MCP Environment Variable Denylist Bypass via Case Sensitivity

Updated under an hour ago (Oct 28, 2026, 12:40 AM ET)

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It affects Flowise and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for Flowise

Exploited in the last 30 days

Flowise before 3.1.3 validates Custom MCP stdio environment variables against a denylist using a case-sensitive comparison, so on Windows, where environment names are case-insensitive, supplying 'node_options' bypasses the NODE_OPTIONS denylist entry. An authenticated user who can configure a Custom MCP node can thereby inject NODE_OPTIONS --require and execute arbitrary code in the Flowise server context.

CVSS: 5.0 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
Weakness (CWE): CWE-178
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Analyzed
Record last updated: Jun 29, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Flowise Flowise flowise:flowise (from the name)	before 3.1.3; 3.1.3 not affected	CNA record
flowiseai flowise flowiseai:flowise	before 3.1.3	NVD

References

References

https://github.com/bikini/exploitarium/tree/main/flowise-mcp-env-case-bypass-poc	exploit, third-party-advisory
https://github.com/FlowiseAI/Flowise/pull/6471	issue-tracking, patch
https://www.vulncheck.com/advisories/flowise-custom-mcp-environment-variable-denylist-bypass-via-case-sensitivity	third-party-advisory, exploit, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.