---
id: "CVE-2026-67542"
page: "https://infrastack.ai/live/CVE-2026-67542"
kind: "vulnerability"
aliases: ["CVE-2026-67542"]
title: "Heym: any logged-in user can make the server fetch arbitrary URLs"
severity: "high"
cvss: 7.1
epss: null
exploited: false
status: "open"
category: "ai-tooling"
products: []
ecosystems: []
tags: ["ai-tooling", "heym", "mcp", "self-hosted"]
not_affected_if: ["auth-required", "managed-hosting"]
published_at: "2026-11-11T22:17:28+00:00"
first_seen_at: "2026-11-11T22:29:35+00:00"
updated_at: "2026-11-11T22:33:55+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-67542", "first_seen_at": "2026-11-11T22:29:35+00:00"}]
exploit_sources: []
---

# Heym: any logged-in user can make the server fetch arbitrary URLs

Link for people: https://infrastack.ai/live/CVE-2026-67542 (this .md is for agents)

Heym's MCP tool-fetch endpoint accepts an attacker-supplied URL and fetches it from the server without checking scheme, private addresses or redirects. A low-privilege authenticated user can use this to reach internal services and read error responses about them.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Heym version and confirm it is below `0.0.70`.
- Look for the `/api/mcp/fetch-tools` route in your deployment and whether it is reachable by ordinary user accounts.

## Fix

- Heym: upgrade to `0.0.70` or later.

## Timeline

- 2026-11-11T22:29:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-67542

## Documents

- [advisory] Vendor advisory: github.com https://github.com/heymrun/heym/security/advisories/GHSA-jjvx-3wfc-p8hq
- [fix] Patch: github.com https://github.com/heymrun/heym/commit/72954f1f6264f6260bc1148b09ca10d613992b64
- [fix] Release notes: github.com https://github.com/heymrun/heym/releases/tag/0.0.70

## From the sources

Heym builds and runs agentic systems and business-process automations on self-hosted infrastructure. Prior to version 0.0.70, POST /api/mcp/fetch-tools is reachable by any authenticated user (lowest role; no admin/workflow association) and fetches an attacker-supplied URL through the sse and streamable_http transports with no scheme / private-IP / allowlist / redirect guard. The transport error is reflected in the HTTP 422 response, giving a semi-blind SSRF oracle, and the attacker also controls the outbound request headers. This issue has been patched in version 0.0.70.

---

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