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Fencer Intel
high 8.8

CVE-2026-67544 json

Heym: Playwright Custom Code Backend RCE via `playwrightCode` Field

published 3mo ago modified 12h ago also GHSA-mp23-7m6r-jfw4 , EUVD-2026-124045

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository heymrun/heym. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
—
no EPSS score yet
public exploits
0
none known

Summary

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.

Patch / fix

Is CVE-2026-67544 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • heymrun heym

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of heymrun/heym published their own advisory on GitHub. Reviewed sources take precedence over it.