CVE-2026-55376
heym Python Tool Sandbox Escape
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Deferred | 3.1 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.46% · top 60% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.
Weakness
- CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') (opens in a new tab)All about CWE-78 and its CVEs
- CWE-94: Improper Control of Generation of Code ('Code Injection') (opens in a new tab)All about CWE-94 and its CVEs
- CWE-693: Protection Mechanism Failure (opens in a new tab)All about CWE-693 and its CVEs
Affected products
References (3)
- https://github.com/heymrun/heym/security/advisories/GHSA-wcgw-9hfw-f6f2 (opens in a new tab)x_refsource_CONFIRMexploit
- https://github.com/heymrun/heym/commit/b36d795c6ea841b8f1b511a0952e274487ee4ef3 (opens in a new tab)x_refsource_MISC
- https://github.com/heymrun/heym/releases/tag/v0.0.40 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-55376)Record last updated .