CVE-2025-59528 | Flowise has Remote Code Execution vulnerability

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Flowise is a drag & drop user interface to build a customized large language model flow. In version 3.0.5, Flowise is vulnerable to remote code execution. The CustomMCP node allows users to input configuration settings for connecting to an external MCP server. This node parses the user-provided mcpServerConfig string to build the MCP server configuration. However, during this process, it executes JavaScript code without any security validation. Specifically, inside the convertToValidJSONString function, user input is directly passed to the Function() constructor, which evaluates and executes the input as JavaScript code. Since this runs with full Node.js runtime privileges, it can access dangerous modules such as child_process and fs. This issue has been patched in version 3.0.6.

Published: 2025-09-22 Last update: 2025-09-23 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2025-59528 is rated High Exploit Risk (94.9/100): CVSS Critical severity, with high exploitation likelihood (EPSS 90.37%, 100th percentile). Core evidence: 2 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +5.10% over the last day, indicating growing attacker interest. Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2025-59528

EDB-ID Source Kind Published Link
52440 exploit_db edb 2025-10-31 Exploit-DB ↗
nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2025-59528

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 85.27% 90.37% +5.10%
2 2026-06-07 86.20% 85.27% -0.94%
3 2026-06-02 86.20%

Full EPSS history (23 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-59528

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
10.0 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 6.0 [email protected]

Weakness enumeration for CVE-2025-59528

GitHub Security Advisory for CVE-2025-59528

GHSA-3gcm-f6qx-ff7p · Severity: critical · Ecosystem: npm — Flowise has Remote Code Execution vulnerability

Affected software / configurations for CVE-2025-59528

Vendor Product Version Raw CPE
flowiseai flowise 3.0.5 cpe:2.3:a:flowiseai:flowise:3.0.5:*:*:*:*:*:*:*

References for CVE-2025-59528

URL Tags
https://github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1f5b9fec81d0/packages/components/nodes/tools/MCP/CustomMCP/CustomMCP.ts#L132 Product
https://github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1f5b9fec81d0/packages/components/nodes/tools/MCP/CustomMCP/CustomMCP.ts#L220 Product
https://github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1f5b9fec81d0/packages/components/nodes/tools/MCP/CustomMCP/CustomMCP.ts#L262-L270 Product
https://github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1f5b9fec81d0/packages/server/src/controllers/nodes/index.ts#L57-L78 Product
https://github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1f5b9fec81d0/packages/server/src/routes/node-load-methods/index.ts#L5 Product
https://github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1f5b9fec81d0/packages/server/src/services/nodes/index.ts#L91-L94 Product
https://github.com/FlowiseAI/Flowise/releases/tag/flowise%403.0.6 Release Notes
https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-3gcm-f6qx-ff7p Exploit Vendor Advisory
cvelogic Threat Intelligence