CVE-2026-55376heym Python Tool Sandbox Escape
Updated under an hour ago ()
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It affects heymrun heym. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.36%, higher than 28% of scored CVEs.
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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.
- CVSS
- 8.8 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-78, CWE-94, CWE-693
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.36% (percentile 28)
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 13, 2026
Affected products
heymrun heym heymrun:heym (from the name) | before 0.0.40 | CNA record |
References
- https://github.com/heymrun/heym/security/advisories/GHSA-wcgw-9hfw-f6f2x-refsource-confirm
- https://github.com/heymrun/heym/commit/b36d795c6ea841b8f1b511a0952e274487ee4ef3x-refsource-misc
- https://github.com/heymrun/heym/releases/tag/v0.0.40x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.