CVE-2026-45226: Heym authorization bypass in workflow execution

CVE-2026-45226 · Severity: high · CVSS 7.1 · Published 2026-05-12

Heym, an automation and workflow platform, contains a security flaw where users can bypass access controls to run workflows belonging to other people. By creating a custom workflow that references a victim's unique workflow ID, an attacker can force the system to execute that private workflow and view its results. This could lead to the exposure of sensitive data or the unauthorized triggering of automated actions, such as sending messages or modifying files, that the victim had configured.

Technologies: Heymrun Heym. Vendors: Heymrun.

Quick answers

Is CVE-2026-45226 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-45226 being exploited in the wild.
How severe is CVE-2026-45226?
High severity, with a CVSS score of 7.1, published 12 May 2026.
Which products and versions are affected?
Heymrun Heym < 0.0.21, before 0.0.21.
Is there a fix for CVE-2026-45226?
A patch was published on 2026-05-10: Fix merged via PR #93 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-45226 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-45226?
Check whether you run Heymrun Heym at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An authorization bypass exists in Heym's workflow execution engine due to insufficient access validation when resolving sub-workflows. While the system correctly validates access to the 'root' workflow, it fails to verify that the actor has permissions for workflows referenced via 'execute' nodes or agent 'subWorkflowIds'. An authenticated attacker who knows or guesses a victim's workflow UUID can embed it into their own workflow; the backend will then load and execute the victim's workflow into the attacker's execution path. This allows the attacker to capture the output of the victim's workflow or trigger its side effects. The vulnerability was addressed in version 0.0.21 by enforcing access checks during the workflow caching process.

Affected products

  • heymrun Heym before 0.0.21

Timeline

  • 2026-05-10: patched: Fix merged via PR #93
  • 2026-05-12: advisory: CVE published

References

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