CVE-2026-55786
flyto-core has Unauthenticated Command Execution via HTTP MCP `execute_module`
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | flyto-core | >= 2.26.2, < 2.26.4 | 2.26.4 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- 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