CVE-2026-67542
Heym: SSRF via POST /api/mcp/fetch-tools: any authenticated user reaches local/private URLs through the SSE and streamable-HTTP transports
Heym builds and runs agentic systems and business-process automations on self-hosted infrastructure. Prior to version 0.0.70, POST /api/mcp/fetch-tools is reachable by any authenticated user (lowest role; no admin/workflow association) and fetches an attacker-supplied URL through the sse and streamable_http transports with no scheme / private-IP / allowlist / redirect guard. The transport error is reflected in the HTTP 422 response, giving a semi-blind SSRF oracle, and the attacker also controls the outbound request headers. This issue has been patched in version 0.0.70.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| heym heymrun |
< 0.0.70 (affected) | CNA: GitHub_M |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 7.1 high |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N | CNA: GitHub_M |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/heymrun/heym/security/advisories/GHSA-jjvx-3wfc-p8hqCNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/heymrun/heym/commit/72954f1f6264f6260bc1148b09ca10d613992b64CNA: GitHub_M · x_refsource_MISC
- https://github.com/heymrun/heym/releases/tag/0.0.70CNA: GitHub_M · x_refsource_MISC
For agents and automation
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Endpoints and access details
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