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.
CVE-2026-39885
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 80% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 23.9%
- KEV
- Not listed
Published
April 8, 2026
Last Modified
April 15, 2026
Advisory Details (2)
Auto-updated Jun 11, 2026SSRF via $ref Dereferencing in Untrusted OpenAPI Specifications · Advisory · agentfront/frontmcp · GitHub
https://github.com/agentfront/frontmcp/security/advisories/GHSA-v6ph-xcq9-qxxjv1.0.4
Patch available: agentfront/frontmcp v1.0.4
https://github.com/agentfront/frontmcp/releases/tag/v1.0.4Affected Packages
(3 across 1 ecosystem)
npm(3)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| @frontmcp/adapters | — | 1.0.4 | — |
| @frontmcp/sdk | — | 1.0.4 | — |
| mcp-from-openapi | — | 2.3.0 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 37× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
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Related CVEs(same CWE)
Same CWE
10 shownCWE-918
Frequently asked(5)
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