CVE-2025-59155

hackmd-mcp server-side request forgery in HTTP transport mode

Published Sep 15, 2025 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed
Description
hackmd-mcp is a Model Context Protocol server for integrating HackMD's note-taking platform with AI assistants. From 1.4.0 to before 1.5.0, hackmd-mcp contains a server-side request forgery (SSRF) vulnerability when the server is run in HTTP transport mode. Arbitrary hackmdApiUrl values supplied via the Hackmd-Api-Url HTTP header or a base64-encoded JSON query parameter are accepted without validation, allowing attackers to redirect outbound API requests to internal network services, access internal endpoints, perform network reconnaissance, and bypass network access controls. The stdio transport mode is not affected because it only accepts stdio requests. The issue is fixed in version 1.5.0, which enforces allowed endpoints and supports the ALLOWED_HACKMD_API_URLS environment variable. Users should update to 1.5.0 or later or apply documented mitigations such as switching to stdio mode, restricting outbound network access, or filtering the Hackmd-Api-Url header and related query parameter via a reverse proxy.

Analysis

No analysis available yet

Remediation

No remediation available yet

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2025-29214 HackMD MCP Server has Server-Side Request Forgery (SSRF) vulnerability
Github GHSA Github GHSA GHSA-g5cg-6c7v-mmpw HackMD MCP Server has Server-Side Request Forgery (SSRF) vulnerability
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description hackmd-mcp is a Model Context Protocol server for integrating HackMD's note-taking platform with AI assistants. From 1.4.0 to before 1.5.0, hackmd-mcp contains a server-side request forgery (SSRF) vulnerability when the server is run in HTTP transport mode. Arbitrary hackmdApiUrl values supplied via the Hackmd-Api-Url HTTP header or a base64-encoded JSON query parameter are accepted without validation, allowing attackers to redirect outbound API requests to internal network services, access internal endpoints, perform network reconnaissance, and bypass network access controls. The stdio transport mode is not affected because it only accepts stdio requests. The issue is fixed in version 1.5.0, which enforces allowed endpoints and supports the ALLOWED_HACKMD_API_URLS environment variable. Users should update to 1.5.0 or later or apply documented mitigations such as switching to stdio mode, restricting outbound network access, or filtering the Hackmd-Api-Url header and related query parameter via a reverse proxy.
Title hackmd-mcp server-side request forgery in HTTP transport mode
Weaknesses CWE-918
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N'}

Subscriptions

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Weaknesses
  • CWE-918

    Server-Side Request Forgery (SSRF)

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 15, 2025, 5:30 PM
Reserved
Sep 9, 2025, 3:23 PM
Status
Deferred
Published
Sep 15, 2025, 5:15 PM
Modified
Jun 17, 2026, 9:45 AM