CVE WatchSep 16, 2026

CVE-2026-59973

FrontMCP is a TypeScript-first framework for the Model Context Protocol (MCP). From mcp-from-openapi 2.3.0 until 2.5.0 and from frontmcp and

CVSS

8.5

High

EPSS

—

KEV

—

Exploit Today

—

0-100

Published: Sep 15, 2026 · Last modified: Sep 16, 2026 · CWE-918

EPSS · 30d

Not enough EPSS history yet.

Technical description

FrontMCP is a TypeScript-first framework for the Model Context Protocol (MCP). From mcp-from-openapi 2.3.0 until 2.5.0 and from frontmcp and @frontmcp/adapters 1.2.1 until 1.5.0, libs/adapters/src/openapi/openapi.adapter.ts loadOpenAPISpec() forwards untrusted OpenAPI url and spec inputs and loadOptions.refResolution to OpenAPIToolGenerator.fromURL() and OpenAPIToolGenerator.fromJSON(). The external $ref guard checks parsed hostname strings without resolving addresses, pinning validated addresses, revalidating redirect targets, or normalizing IPv4-mapped IPv6. An authenticated user who can import or configure an OpenAPI specification in a hosted or multi-user deployment can use DNS-to-loopback resolution, redirect-to-loopback behavior, or IPv4-mapped IPv6 loopback forms to cause backend-origin requests to internal services. This can expose internal administrative APIs, metadata-like services, and other private network endpoints. The practical impact is lower when only a trusted local administrator can configure OpenAPI specs, and disabling external reference protocols prevents the external $ref request. This issue is fixed in mcp-from-openapi 2.5.0 and frontmcp and @frontmcp/adapters 1.5.0.

Official references

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-927197.5 HIG

—

———Quickwit through 0.9.0 fails to validate the host and scheme of the queue_url parameter in SQS file sources, allowing attackers to make the node issue requests to arbitrary internal addresses. Attackers can supply a malicious queue_url to the create-source API to scan internal networks and fingerprint services based on connection response differences.3h CVE-2026-926027.1 HIG

—

———TDuck survey form through version 5.3 fails to validate webhook URLs or verify form ownership in the WebhookConfigController. Authenticated attackers can attach webhooks to other users' forms and exfiltrate submissions to arbitrary external or internal addresses.4h CVE-2026-857324.7 MED

—

———oras-go is a Go library for managing OCI artifacts. Prior to 2.6.2, the parseLink function in registry/remote/utils.go accepts an absolute URL from a registry-controlled Link response header without validating its scheme, host, or port. Tags, Referrers, and Repositories pagination operations then issue a GET request to the attacker-selected URL from the victim's network, allowing blind server-side request forgery against internal services. The response body is not returned to the attacker, but timing and error differences can reveal service reachability, and credentials may be attached when the credential store has an entry for the target host. Exploitation requires a victim to perform a pagination-based listing operation against a malicious registry. The maintainer identifies this report as a duplicate of GHSA-3hr5-mjrr-hfjh and states that remediation is consolidated in that earlier advisory. The consolidated issue is fixed in version 2.6.2.3h CVE-2026-925694.3 MED

—

———Hippo4j through 1.5.0 contains a server-side request forgery vulnerability in four ThreadPoolController endpoints that fail to validate the clientAddress parameter. Authenticated attackers can supply arbitrary hostnames and ports to trigger outbound GET requests to internal networks and cloud metadata services.6h CVE-2026-925685.4 MED

—

———MLRun through 1.11.0 contains a server-side request forgery vulnerability in the WebhookNotification handler that allows authenticated users to make the API server send arbitrary HTTP requests to internal addresses. Attackers can update a run with a malicious webhook notification that executes when the run reaches a terminal state, enabling requests to internal services, Kubernetes APIs, or cloud metadata endpoints from within the cluster.5h CVE-2026-925668.2 HIG

—

———DataGear through 6.0.0 contains a server-side request forgery vulnerability in the /dataSet/preview/Http endpoint that allows unauthenticated attackers to execute arbitrary HTTP requests by supplying a caller-controlled URI. Attackers can issue GET, POST, PUT, PATCH, or DELETE requests to internal endpoints and cloud metadata services, receiving full response bodies without authentication or validation.5h