CVE-2026-39885
Description
FrontMCP is a TypeScript-first framework for the Model Context Protocol (MCP). Prior to 2.3.0, the mcp-from-openapi library uses @apidevtools/json-schema-ref-parser to dereference $ref pointers in OpenAPI specifications without configuring any URL restrictions or custom resolvers. A malicious OpenAPI specification containing $ref values pointing to internal network addresses, cloud metadata endpoints, or local files will cause the library to fetch those resources during the initialize() call. This enables Server-Side Request Forgery (SSRF) and local file read attacks when processing untrusted OpenAPI specifications. This vulnerability is fixed in 2.3.0.
How to fix
- agentfront frontmcp1.0.4 or later
- agentfront \@frontmcp\/adapters1.0.4 or later
- agentfront \@frontmcp\/sdk1.0.4 or later
- frontmcp mcp-from-openapi2.3.0 or later
- mcp-from-openapi2.3.0 or later
- @frontmcp/sdk1.0.4 or later
- @frontmcp/adapters1.0.4 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| agentfront frontmcp | v < 1.0.4 | 1.0.4 |
| agentfront \@frontmcp\/adapters | v < 1.0.4 | 1.0.4 |
| agentfront \@frontmcp\/sdk | v < 1.0.4 | 1.0.4 |
| frontmcp mcp-from-openapi | v < 2.3.0 | 2.3.0 |
| mcp-from-openapinpm | v < 2.3.0 | 2.3.0 |
| @frontmcp/sdknpm | v < 1.0.4 | 1.0.4 |
| @frontmcp/adaptersnpm | v < 1.0.4 | 1.0.4 |
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