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.
Metrics
Affected Vendors & Products
References
History
Fri, 13 Nov 2026 07:45:00 +0000
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Wed, 11 Nov 2026 21:45:00 +0000
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| 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 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-11-11T21:41:03.020Z
Updated: 2026-11-12T17:54:44.721Z
Reserved: 2026-07-29T18:47:17.074Z
Link: CVE-2026-67546
No data.
Status : Deferred
Published: 2026-11-11T22:17:29.533
Modified: 2026-11-12T18:17:52.973
Link: CVE-2026-67546
No data.