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

> Authenticated users can escape the Python sandbox to execute arbitrary host commands and access sensitive backend credentials.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 May 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-vhhj-j98h-xx8p

## What is CVE-2026-45227?

CVE-2026-45227 is a high-severity code injection vulnerability in heymrun heym, published on 12 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-45227?


## How do I fix CVE-2026-45227?

No fix has been published for CVE-2026-45227 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-45227 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-45227 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-45227 and fix it if it is affected.

What it is: CVE-2026-45227 is a high-severity code injection vulnerability in heymrun heym, published on 12 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-45227 exists.

Affected product: heymrun heym. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-45227/ (Markdown: https://insights.sbomify.com/CVE-2026-45227/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45227
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45227
- OSV: https://osv.dev/vulnerability/CVE-2026-45227

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-45227/
Summaries are generated and may contain mistakes; the official description above is the record.