heymrun Heym up to 0.0.39 Python Tool Executor python_tool_executor.py exec privileges management

Summaryinfo

A vulnerability was found in heymrun Heym up to 0.0.39. It has been rated as critical. The affected element is the function exec of the file backend/app/services/python_tool_executor.py of the component Python Tool Executor. Performing a manipulation results in privileges management. This vulnerability was named CVE-2026-55376. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical has been found in heymrun Heym up to 0.0.39. This affects the function exec of the file backend/app/services/python_tool_executor.py of the component Python Tool Executor. The manipulation with an unknown input leads to a privileges management vulnerability. CWE is classifying the issue as CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-55376 since 06/16/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1068 for this issue.

Upgrading to version 0.0.40 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• heymrun

Name

• Heym

Version

• 0.0.1
• 0.0.2
• 0.0.3
• 0.0.4
• 0.0.5
• 0.0.6
• 0.0.7
• 0.0.8
• 0.0.9
• 0.0.10
• 0.0.11
• 0.0.12
• 0.0.13
• 0.0.14
• 0.0.15
• 0.0.16
• 0.0.17
• 0.0.18
• 0.0.19
• 0.0.20
• 0.0.21
• 0.0.22
• 0.0.23
• 0.0.24
• 0.0.25
• 0.0.26
• 0.0.27
• 0.0.28
• 0.0.29
• 0.0.30
• 0.0.31
• 0.0.32
• 0.0.33
• 0.0.34
• 0.0.35
• 0.0.36
• 0.0.37
• 0.0.38
• 0.0.39

Website

• Product: https://github.com/heymrun/heym/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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