CVE-2026-45227

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.

Is your site exposed to CVE-2026-45227?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0005

Probability of exploitation

0.16%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-693 CWE-693

References

Other 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

Frequently Asked Questions

What is CVE-2026-45227? +

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. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-45227? +

CVE-2026-45227 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0005, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-45227? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2025-3114

Code Execution via Malicious Files: Attackers can create specially crafted files with embedded code that may execute without adequate security …

CVE-2024-51481

Nix is a package manager for Linux and other Unix systems. On macOS, built-in builders (such as `builtin:fetchurl`, exposed to …

CVE-2025-65100

Isar is an integration system for automated root filesystem generation. In versions 0.11-rc1 and 0.11, defining ISAR_APT_SNAPSHOT_DATE alone does not …

CVE-2025-29864

Protection Mechanism Failure vulnerability in ESTsoft ALZip on Windows allows SmartScreen bypass.This issue affects ALZip: from 12.01 before 12.29.

CVE-2025-66479

Anthropic Sandbox Runtime is a lightweight sandboxing tool for enforcing filesystem and network restrictions on arbitrary processes at the OS …

CVE-2025-34413

Legality WHISTLEBLOWING by DigitalPA contains a protection mechanism failure in which critical HTTP security headers are not emitted by default. …