Vulnerability · Published Oct 14, 2026 · Assigned by GitHub_M
CVE-2026-55786Flyto2 Core: Unauthenticated Command Execution via HTTP MCP `execute_module`
High 8.4
In plain English
A high-severity OS command injection in flyto-core from flytohub. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | flyto-core | 2.26.4 | GHSA-h9f9-h6gm-wc85 |
| PyPI | flyto-core | 2.26.4 | PYSEC-2026-2482 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| flytohub | flyto-core | >= 2.26.2, < 2.26.4 |
Weakness: CWE-78, CWE-306 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H