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CVE-2026-55376— heym Python Tool Sandbox Escape

Quick assessment

Affected
heymrun heym
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Heym 在自有基础设施上构建和运行智能体系统及业务流程自动化工具。在 0.0.40 版本之前，一个拥有创建工作流或使用具备 Agent 自定义 Python 工具权限的经过认证的用户，可以绕过后端/app/services/python_tool_executor.py 中基于黑名单的沙箱机制。这是因为允许使用的标准库模块通过公共属性暴露了操作系统、进程和文件系统功能，而这些属性能够顺利通过 _safe_import() 和 _validate_code_safety() 的安全检查。随后，系统会使用 exec(

CVSS 8.8 · High EPSS 0.36% · P28

Affected Version Matrix 1

VendorProduct Version RangeStatus
heymrun heym < 0.0.40 affected
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I. Basic Information for CVE-2026-55376

Vulnerability Information
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Vulnerability Title
heym Python Tool Sandbox Escape
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
OS命令中使用的特殊元素转义处理不恰当(OS命令注入)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
heymrun heym < 0.0.40 -

II. Public POCs for CVE-2026-55376

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III. Intelligence Information for CVE-2026-55376

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Vendor Advisories for CVE-2026-55376 (1)

Proof of Concept for CVE-2026-55376 (1)

IV. Related Vulnerabilities

Same product: heym
Same vendor: heymrun
Same weakness: CWE-78

V. Comments for CVE-2026-55376

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