CVE-2026-39885
Published:April 08, 2026
Updated:April 20, 2026
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.
Affected Packages
mcp-from-openapi (NPM):
Affected version(s) >=0.0.1 <2.3.0Fix Suggestion:
Update to version 2.3.0@frontmcp/adapters (NPM):
Affected version(s) >=0.1.2 <1.0.4Fix Suggestion:
Update to version 1.0.4@frontmcp/sdk (NPM):
Affected version(s) >=0.1.0 <1.0.4Fix Suggestion:
Update to version 1.0.4@frontmcp/adapters (NPM):
Affected version(s) >=0.1.2 <1.0.4Fix Suggestion:
Update to version 1.0.4@frontmcp/sdk (NPM):
Affected version(s) >=0.1.0 <1.0.4Fix Suggestion:
Update to version 1.0.4mcp-from-openapi (NPM):
Affected version(s) >=0.0.1 <2.3.0Fix Suggestion:
Update to version 2.3.0Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Weakness Type (CWE)
Server-Side Request Forgery (SSRF)
EPSS
Base Score:
0.04
