CVE-2026-39885
FrontMCP Affected by SSRF via $ref Dereferencing in Untrusted OpenAPI Specifications
Vexday Risk Score
21Low
SSVC decision (CISA)
Track
No exploitation signal → monitor
CVSS 7.5EPSS 0.3%KEV nãoPoC —Nuclei —Metasploit —Patch —
Lifecycle
08 Apr 2026Published on NVD
Recommendation: Monitor — no exploitation signal at the moment.
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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Affected products
agentfront · frontmcp@frontmcp · adapters@frontmcp · sdkfrontmcp · mcp-from-openapiWant to know if your infrastructure is exposed to this?
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