What’s Vulnerable › Vulnerabilities

CVE-2026-55376: heym Python Tool Sandbox Escape

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-13 · updated 2026-10-16
• Weakness: CWE-78

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.

Affected products

• heymrun heym: before 0.0.40

References

• https://github.com/heymrun/heym/commit/b36d795c6ea841b8f1b511a0952e274487ee4ef3
• https://github.com/heymrun/heym/releases/tag/v0.0.40
• https://github.com/heymrun/heym/security/advisories/GHSA-wcgw-9hfw-f6f2
• https://github.com/heymrun/heym/security/advisories/GHSA-wcgw-9hfw-f6f2

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