CVE-2026-39885
CVE-2026-39885 · FrontMCP Affected by SSRF via $ref Dereferencing in Untrusted OpenAPI Specifications
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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.
CVSS 7.5 · High · EPSS 0.4% · Fix available
- Published
- Updated
Stack: node
Affected products and versions
frontmcp
- Versions
- < 1.0.4: Affected
No fix published
adapters
- Versions
- < 1.0.4: Affected
No fix published
sdk
- Versions
- < 1.0.4: Affected
No fix published
mcp-from-openapi
- Versions
- < 2.3.0: Affected
No fix published
mcp-from-openapi npm
- Affected ranges
- SEMVER: < 2.3.0
Update to 2.3.0
@frontmcp/sdk npm
- Affected ranges
- SEMVER: < 1.0.4
Update to 1.0.4
@frontmcp/adapters npm
- Affected ranges
- SEMVER: < 1.0.4
Update to 1.0.4