CVE-2026-39885Public exploitNetwork attack vector

Server resource disclosure via unrestricted $ref dereferencing

Published Apr 8, 2026 · Updated Apr 8, 2026

SSRF in AgentFront FrontMCP before 1.0.4 and mcp-from-openapi before 2.3.0 allows remote attackers to read server-reachable resources. OpenAPIToolGenerator.initialize() passes an untrusted OpenAPI document to json-schema-ref-parser dereference() without URL, protocol, host, or file restrictions. Exploitation requires an application to process an attacker-supplied specification; the resulting requests can expose internal services, cloud metadata credentials, or local file contents.

CVSS severity7.5
High
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

SSRF in AgentFront FrontMCP before 1.0.4 and mcp-from-openapi before 2.3.0 allows remote attackers to read server-reachable resources. OpenAPIToolGenerator.initialize() passes an untrusted OpenAPI document to json-schema-ref-parser dereference() without URL, protocol, host, or file restrictions. Exploitation requires an application to process an attacker-supplied specification; the resulting requests can expose internal services, cloud metadata credentials, or local file contents.

The record

CVE
CVE-2026-39885
Published
Apr 8, 2026
Updated
Apr 8, 2026
Vendor
AgentFront
Product
@frontmcp/adapters
Classifications
CWE-918, T1552.001, T1552.005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.0.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

AgentFront · @frontmcp/adaptersversion=< 1.0.4
AgentFront · FrontMCPversion=< 1.0.4
AgentFront · mcp-from-openapiversion=< 2.3.0
AgentFront · @frontmcp/sdkversion=< 1.0.4

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1552.001Unsecured Credentials: Credentials In Files
T1552.005Unsecured Credentials: Cloud Instance Metadata API

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo