FrontMCP Affected by SSRF via $ref Dereferencing in Untrusted OpenAPI Specifications

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Summary

CVECVE-2026-39885
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-08 21:17:00 UTC
Updated2026-04-15 19:04:51 UTC
DescriptionFrontMCP 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS: 0.000420000 probability, percentile 0.125050000 (date 2026-04-15)

Problem Types: CWE-918 | CWE-918 CWE-918: Server-Side Request Forgery (SSRF)

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Agentfront Frontmcp All All All All
Application Agentfront @frontmcp/adapters All All All All
Application Agentfront @frontmcp/sdk All All All All
Application Frontmcp Mcp-from-openapi All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Agentfront Frontmcp affected < 1.0.4 Not specified
CNA @frontmcp Adapters affected < 1.0.4 Not specified
CNA @frontmcp Sdk affected < 1.0.4 Not specified
CNA Frontmcp Mcp-from-openapi affected < 2.3.0 Not specified

References

ReferenceSourceLinkTags
github.com/agentfront/frontmcp/releases/tag/v1.0.4 [email protected] github.com Product
github.com/agentfront/frontmcp/security/advisories/GHSA-v6ph-xcq9-qxxj 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com Exploit, Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
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