Low
Flowise - Custom MCP Environment Variable Denylist Bypass via Case Sensitivity
Type: advisorySources: OSV
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-58057
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 13:31 UTC · Revision 1
Source evidence
Flowise - Custom MCP Environment Variable Denylist Bypass via Case Sensitivity
core-osv · Original sourcePublished 28 Jun 2026, 01:32 UTC
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.
osv:CVE-2026-58057
Complete source record
{
"id": "0c86d5626ecdbd6aad5a1bffe8bd1830113c87b499e34f6f8d08ce4d9c555151",
"url": "https://osv.dev/vulnerability/CVE-2026-58057",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Flowise - Custom MCP Environment Variable Denylist Bypass via Case Sensitivity",
"summary": "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.",
"evidence": "osv:CVE-2026-58057",
"products": [],
"severity": "low",
"structured": {
"id": "CVE-2026-58057",
"aliases": [
"CVE-2026-58057"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/flowiseai/flowise",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "09f099dbfda179e439ec677d06ad737375899eef"
}
],
"database_specific": {
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "3.1.3"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"cpe": "cpe:2.3:a:flowiseai:flowise:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "3.1.3"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-58057.json"
}
}
],
"modified": "2026-10-28T02:30:28.991707617Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58057.json",
"https://nvd.nist.gov/vuln/detail/CVE-2026-58057",
"https://www.vulncheck.com/advisories/flowise-custom-mcp-environment-variable-denylist-bypass-via-case-sensitivity",
"https://github.com/FlowiseAI/Flowise/pull/6471",
"https://github.com/bikini/exploitarium/tree/main/flowise-mcp-env-case-bypass-poc"
],
"provider_metadata": {
"cwe_ids": [
"CWE-178"
],
"cna_assigner": "VulnCheck",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58057.json"
}
},
"related_cves": [
{
"value": "CVE-2026-58057",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 495903,
"published_at": "2026-06-28T01:32:58.594+00:00"
}