CVE-2026-39885
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.32%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 0.32% probability · 25th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-918
- Affected
- agentfront/\@frontmcp\/adapters · agentfront/\@frontmcp\/sdk · agentfront/frontmcp · frontmcp/mcp-from-openapi
- Source
- security-advisories@github.com
References
- https://github.com/agentfront/frontmcp/releases/tag/v1.0.4Product
- https://github.com/agentfront/frontmcp/security/advisories/GHSA-v6ph-xcq9-qxxjExploit, Vendor Advisory
- https://github.com/agentfront/frontmcp/security/advisories/GHSA-v6ph-xcq9-qxxjExploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.