heym before 0.0.91 Remote Code Execution via Expression Engine (CVE-2026-100864) | HOL Guard CVE

High · CVSS 8.7CVE-2026-100864

heym before 0.0.91 Remote Code Execution via Expression Engine

Answer in brief

CVE-2026-100864 records a High severity (CVSS 8.7) vulnerability in heym before 0.0.91 Remote Code Execution via Expression Engine. 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 Sep 27, 2026Updated Sep 27, 2026Source checked Sep 27, 2026First seen by HOL Sep 27, 2026Material review Sep 27, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.7
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.7. 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 <0.0.91	0.0.91

Recommended response

Check inventory. Check lockfiles and deployed manifests for heymrun/heym.
Review the reported fix. Update heymrun/heym to 0.0.91 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 27, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 27, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 27, 2026

Sources and claim methodology

Upstream source description

heym before 0.0.91 contains a sandbox escape vulnerability in the expression engine's DotList map/filter and fallback resolver that allows authenticated users to execute arbitrary Python code. Attackers can craft workflow expressions using dunder attribute access through item expressions or the fallback resolver to access os.system and execute commands as the backend process.

Quoted source text, attributed separately from HOL analysis.