CVSS 3.1
7.1 highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:NCVE-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) in heymrun heym. EPSS 0.3% estimated probability of exploitation activity in the next 30 days.
On this page
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.
Severity
- EPSS
- 0.3% estimated probability of exploitation activity in the next 30 days; 28th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-12. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-918 Server-Side Request Forgery (SSRF)
- OWASP Top 10
- A01:2025 Broken Access Control
- Published
- Modified
- Assigned by
- GitHub_M (CNA)
- NVD analysis
- Deferred: the NVD does not plan to analyze it
- Record from
- the NVD, synced
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Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| heymrun heym | < 0.0.70 |
Attack patterns (CAPEC)
- CAPEC-664 Server Side Request Forgery Likelihood: High · Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.
History
- The NVD deferred its analysis
Changes since this site first stored the record. The same for every record: /api/public/changes.