Heym builds and runs agentic systems and business-process automations on self-hosted infrastructure. Prior to version 0.0.75, the same POST /api/mcp/fetch-tools endpoint (any authenticated user, lowest role) also accepts the stdio transport, which spawns the attacker-supplied command with attacker-supplied args and an environment merged over os.environ. The process executes on the shared backend host before MCP protocol validation fails — so side effects fire regardless of whether the command speaks MCP. This is a distinct weakness class and exploit primitive from the SSRF (Advisory 2) on the same endpoint, and needs a different fix (role gating / opt-in trust boundary rather than egress controls). This issue has been patched in version 0.0.75.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| heymrun | heym | affected |
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References
History
Wed, 11 Nov 2026 21:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Heym builds and runs agentic systems and business-process automations on self-hosted infrastructure. Prior to version 0.0.75, the same POST /api/mcp/fetch-tools endpoint (any authenticated user, lowest role) also accepts the stdio transport, which spawns the attacker-supplied command with attacker-supplied args and an environment merged over os.environ. The process executes on the shared backend host before MCP protocol validation fails — so side effects fire regardless of whether the command speaks MCP. This is a distinct weakness class and exploit primitive from the SSRF (Advisory 2) on the same endpoint, and needs a different fix (role gating / opt-in trust boundary rather than egress controls). This issue has been patched in version 0.0.75. | |
| Title | Heym: Command execution via POST /api/mcp/fetch-tools stdio transport: supplied command is spawned before MCP validation | |
| Weaknesses | CWE-94 | |
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| Metrics |
cvssV3_1
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MITRE
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-11-11T21:41:03.020Z
Reserved: 2026-07-29T18:47:17.074Z
Link: CVE-2026-67546
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NVD
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Redhat
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OpenCVE Enrichment
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Weaknesses