Auth bypass in Heymrun Heym
CVE-2026-45226
Heym before 0.0.21 contains an authorization bypass vulnerability in workflow execution that allows authenticated users to execute arbitrary workflows by referencing victim workflow UUIDs without proper access validation. Attackers can create workflows with execute nodes or agent subWorkflowIds pointing to victim workflow UUIDs to load and execute those workflows under attacker-controlled execution paths, exposing victim workflow outputs and triggering workflow nodes with unintended side effects.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L.
EPSS exploit prediction
EPSS: 0.005 (39.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 39.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002
Affected products
- Heymrun Heym — versions 0, 3ae3ef6a7d3609da0e910f9ed6b81e99a1661ac8
Weakness classification (CWE)
References
- github.com/heymrun/heym/releases/tag/v0.0.21 (release-notes)
- github.com/heymrun/heym/pull/93 (issue-tracking)
- github.com/heymrun/heym/commit/3ae3ef6a7d3609da0e910f9ed6b81e99a1661ac8 (patch)
- www.vulncheck.com/advisories/heym-authorization-bypass-in-workflow-execution (third-party-advisory)
Frequently asked questions
- What is CVE-2026-45226?
- CVE-2026-45226 is a high-severity vulnerability in Heymrun Heym, classified under Incorrect Authorization. CVSS score: 7.1/10. Published 2026-05-12.
- How severe is CVE-2026-45226?
- High severity. CVSS v3 base score is 7.1 out of 10.