How severe is CVE-2026-39885?

CVE-2026-39885 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-39885 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39885?

CVE-2026-39885 primarily affects Agentfront @frontmcp/adapters. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-39885?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-39885 have an EU (EUVD) identifier?

Yes. CVE-2026-39885 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20632.

When was CVE-2026-39885 published?

CVE-2026-39885 was published on 2026-04-08 and last updated on 2026-06-17.

CVE-2026-39885

CVE-2026-39885 is a high-severity vulnerability in Agentfront @frontmcp/adapters with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-918.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-20632
Weakness: CWE-918
Affected product: Agentfront @frontmcp/adapters
Published: 2026-04-08
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-39885?: 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.
How severe is CVE-2026-39885?: CVE-2026-39885 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-39885 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39885?: CVE-2026-39885 primarily affects Agentfront @frontmcp/adapters. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-39885?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-39885 have an EU (EUVD) identifier?: Yes. CVE-2026-39885 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20632.
When was CVE-2026-39885 published?: CVE-2026-39885 was published on 2026-04-08 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:agentfront:\@frontmcp\/adapters:*:*:*:*:*:node.js:*:*
cpe:2.3:a:agentfront:\@frontmcp\/sdk:*:*:*:*:*:node.js:*:*
cpe:2.3:a:agentfront:frontmcp:*:*:*:*:*:node.js:*:*
cpe:2.3:a:frontmcp:mcp-from-openapi:*:*:*:*:*:node.js:*:*

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