---
id: CVE-2026-55376
title: >-
  Heym builds and runs agentic systems and business-process automations on
  self-hosted infrastructure
summary: >-
  Heym builds and runs agentic systems and business-process automations on
  self-hosted infrastructure. Prior to 0.0.40, an authenticated user who can
  create or edit a workflow with an Agent custom Python tool can bypass the
  blacklist-based…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-78
  - CWE-94
  - CWE-693
published: '2026-10-13'
updated: '2026-10-13'
sourceUpdated: '2026-10-13T16:17:21.853'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55376'
references:
  - url: >-
      https://github.com/heymrun/heym/commit/b36d795c6ea841b8f1b511a0952e274487ee4ef3
    label: security-advisories@github.com
  - url: 'https://github.com/heymrun/heym/releases/tag/v0.0.40'
    label: security-advisories@github.com
  - url: 'https://github.com/heymrun/heym/security/advisories/GHSA-wcgw-9hfw-f6f2'
    label: security-advisories@github.com
tags:
  - nvd
ingestedAt: '2026-10-13T16:35:46.742Z'
---

## Overview

Heym builds and runs agentic systems and business-process automations on self-hosted infrastructure. Prior to 0.0.40, an authenticated user who can create or edit a workflow with an Agent custom Python tool can bypass the blacklist-based sandbox in backend/app/services/python_tool_executor.py because allowed standard-library modules expose operating-system, process, and filesystem capabilities through public attributes that pass _safe_import() and _validate_code_safety(). The runner then executes the supplied tool with exec(), permitting commands and file operations as the backend application user; self-registration affects reachability, but portal triggering alone does not grant code control. This issue is fixed in 0.0.40.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.