High 8.4Published Oct 14, 2026

CVE-2026-55786Flyto2 Core: Unauthenticated Command Execution via HTTP MCP `execute_module`

Updated under an hour ago (2026-10-19 08:00 UTC)

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It affects flytohub flyto-core. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.26%, higher than 16% of scored CVEs.

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Exploited in the last 30 days

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.

CVSS: 8.4 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-78, CWE-306
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.26% (percentile 16)
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Oct 14, 2026
First seen by InfoSec Signals: Oct 14, 2026

Affected products

Affected products

flytohub flyto-core flytohub:flyto_core (from the name)	from 2.26.2, < 2.26.4	CNA record

References

https://github.com/flytohub/flyto-core/security/advisories/GHSA-h9f9-h6gm-wc85x-refsource-confirm
https://github.com/flytohub/flyto-core/commit/db7f116b1d3c5dcf94aded00d14118f81f3e225ex-refsource-misc
https://github.com/flytohub/flyto-core/releases/tag/v2.26.4x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.