flyto-core has Unauthenticated Command Execution via HTTP MCP `execute_module`

Why it is Yellow

• CVSS 8.4 high
• On your watchlist: PyPI

Affected packages

References

• https://github.com/advisories/GHSA-h9f9-h6gm-wc85
• https://github.com/flytohub/flyto-core/security/advisories/GHSA-h9f9-h6gm-wc85
• https://nvd.nist.gov/vuln/detail/CVE-2026-55786
• https://github.com/flytohub/flyto-core/commit/db7f116b1d3c5dcf94aded00d14118f81f3e225e
• https://github.com/flytohub/flyto-core/releases/tag/v2.26.4
• https://github.com/pypa/advisory-database/tree/main/vulns/flyto-core/PYSEC-2026-2482.yaml
• https://github.com/advisories/GHSA-h9f9-h6gm-wc85

Original description

Flyto2 Core is an execution kernel for automation and AI-agent workflows. From 2.26.2 until 2.26.4, the HTTP MCP POST /mcp route accepts unauthenticated JSON-RPC tools/call requests and forwards execute_module arguments to the module registry without the require_auth dependency used by the REST execution routes. An unauthenticated caller can select sandbox.execute_shell and supply its command parameter, which reaches asyncio.create_subprocess_shell with the privileges of the flyto-core server process. The endpoint is reachable locally under the default loopback binding and becomes network reachable when an operator binds the server to a non-loopback interface, allowing arbitrary OS command execution and potential full host compromise. This issue is fixed in version 2.26.4.