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
- High 7.1
Description
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.
Key facts
- Published
- 11 Nov 2026
- Last changed
- 12 Nov 2026
- Assigned by
- GitHub_M
- EPSS
- 0.342% likely to be exploited in the next 30 days, higher than 28.08% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: none; Automatable: no; Technical impact: partial
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 7.1CVSS 3.1, Highfrom the CNA (GitHub_M)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
No explicit remediation statement is available on this page yet. Consult the original record and vendor references before choosing a fix.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| heymrun | heym |
|
Timeline
- 11 Nov 2026 Published