High · CVSS 8.8CVE-2026-55376

heym Python Tool Sandbox EscapeCVE-2026-55376

Answer in brief

CVE-2026-55376 records a High severity (CVSS 8.8) vulnerability in heym Python Tool Sandbox Escape. The current sources do not mark it as known exploited. The current feed maps heymrun/heym (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 13, 2026Updated Oct 13, 2026Source checked Oct 13, 2026First seen by HOL Oct 13, 2026Material review Oct 13, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.8
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps heymrun/heym (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
heymrun/heymgeneric	<0.0.40	0.0.40

Recommended response

Check inventory. Check lockfiles and deployed manifests for heymrun/heym.
Review the reported fix. Update heymrun/heym to 0.0.40 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 13, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.