What’s Vulnerable › Vulnerabilities

CVE-2026-45227: Heym < 0.0.21 Sandbox Escape via Python Introspection

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-12 · updated 2026-10-26
• Weakness: CWE-693

Description

Heym before 0.0.21 contains a sandbox escape vulnerability in the custom Python tool executor that allows authenticated workflow authors to bypass sandbox restrictions by using object-graph introspection primitives. Attackers can use Python introspection techniques to recover the unrestricted __import__ function, import blocked modules such as os and subprocess, and access inherited backend environment variables containing database credentials and encryption keys to execute arbitrary host commands as the backend service user.

Affected products

• heymrun heym: before 0.0.21 — fixed in 0.0.21

How to fix

Upgrade to a fixed version: heymrun heym 0.0.21. Check the vendor advisory for mitigations.

References

• https://github.com/heymrun/heym/commit/32b7e809d987d9b018ec8daa2cdaf48f627f26f1
• https://github.com/heymrun/heym/pull/94
• https://github.com/heymrun/heym/releases/tag/v0.0.21
• https://www.vulncheck.com/advisories/heym-sandbox-escape-via-python-introspection
• https://github.com/heymrun/heym/pull/94

Get alerted when CVE-2026-45227 or the next vulnerability affects your stack