CVE-2026-55786: flyto-core has Unauthenticated Command Execution via HTTP MCP `execute_module`
(updated )
The HTTP MCP endpoint (POST /mcp) in flyto-core accepts unauthenticated JSON-RPC tools/call requests and dispatches them to arbitrary registered modules, including sandbox.execute_shell, which passes attacker-controlled input directly to asyncio.create_subprocess_shell. An unauthenticated attacker can execute arbitrary OS commands as the flyto-core server process. By default the server binds to 127.0.0.1, making this a High-severity local vulnerability (CVSS 8.4); if started with --host 0.0.0.0, it becomes remotely exploitable over the network. Dynamic reproduction confirmed command execution as root inside a Docker container without any Authorization header.
References
- github.com/advisories/GHSA-h9f9-h6gm-wc85
- github.com/flytohub/flyto-core/commit/db7f116b1d3c5dcf94aded00d14118f81f3e225e
- github.com/flytohub/flyto-core/releases/tag/v2.26.4
- github.com/flytohub/flyto-core/security/advisories/GHSA-h9f9-h6gm-wc85
- github.com/pypa/advisory-database/tree/main/vulns/flyto-core/PYSEC-2026-2482.yaml
- nvd.nist.gov/vuln/detail/CVE-2026-55786
Code Behaviors & Features
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