Heym Sandbox Escape Vulnerability (CVE-2026-45227) Allows Arbitrary Host Commands
The National Vulnerability Database has detailed CVE-2026-45227, a critical sandbox escape vulnerability affecting Heym before version 0.0.21. This flaw resides within the custom Python tool executor, allowing authenticated workflow authors to completely bypass sandbox restrictions. Attackers can leverage Python object-graph introspection to recover the unrestricted __import__ function.
This capability enables the import of blocked modules, specifically os and subprocess, granting access to inherited backend environment variables. These variables often contain sensitive data like database credentials and encryption keys. The ultimate impact is severe: attackers can execute arbitrary host commands as the backend service user, effectively achieving full system compromise. The National Vulnerability Database assigns a CVSS score of 8.8 (HIGH), reflecting the critical nature of this vulnerability.
This isn’t just a sandbox bypass; it’s a direct path to full RCE and sensitive data exfiltration. The attacker’s calculus here is simple: gain authenticated access to a workflow, exploit the introspection, and own the backend. Defenders need to recognize that even ‘authenticated’ access can be a low bar in some environments, making this a high-value target for threat actors.
What This Means For You
- If your organization uses Heym, patch to version 0.0.21 or later immediately. This vulnerability allows for a complete sandbox escape and arbitrary command execution, meaning an authenticated attacker can compromise your backend systems. Audit your Heym environments for any unusual activity or unauthorized module imports.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2026-45227 - Heym Sandbox Escape - Arbitrary Host Command Execution via Python Introspection
title: CVE-2026-45227 - Heym Sandbox Escape - Arbitrary Host Command Execution via Python Introspection
id: scw-2026-05-12-ai-1
status: experimental
level: critical
description: |
Detects the execution of Python interpreters with commands indicative of the Heym sandbox escape vulnerability (CVE-2026-45227). Attackers exploit this by using object-graph introspection primitives to recover and use functions like `__import__` to load modules such as 'os' and 'subprocess', enabling arbitrary host command execution. This rule specifically looks for Python execution with these suspicious import patterns in the command line.
author: SCW Feed Engine (AI-generated)
date: 2026-05-12
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-45227/
tags:
- attack.execution
- attack.t1059.006
logsource:
category: process_creation
detection:
selection:
Image|startswith:
- 'C:\Python\Python39\python.exe'
- '/usr/bin/python3'
CommandLine|contains:
- 'import os'
- 'import subprocess'
- '__import__('
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-45227 | Sandbox Escape | Heym before 0.0.21 |
| CVE-2026-45227 | RCE | custom Python tool executor |
| CVE-2026-45227 | Information Disclosure | access inherited backend environment variables containing database credentials and encryption keys |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 13, 2026 at 01:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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