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Vulnerabilities

Vulnerability · CVE-2026-55786

Flyto2 Core is an execution kernel for automation and AI-agent workflows.

Published Jul 6, 2026 · catalog updated Oct 14, 2026 · FlytoHub Flyto2 Core

Patch now

CVE-2026-55786 is in the CISA known-exploited catalog. Confirm FlytoHub Flyto2 Core against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
High8.4
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
0.26%
Remediation
Remediation guidance
Affected products
PyPI flyto-core · vendor FlytoHub Flyto2 Core

## Unauthenticated Command Execution via HTTP MCP ### Summary The HTTP MCP endpoint ( ) in flyto-core accepts unauthenticated JSON-RPC requests and dispatches them to arbitrary registered modules, including , which passes attacker-controlled input directly to . An unauthenticated attacker can execute arbitrary OS commands as the flyto-core server process. By default the server binds to , making this a High-severity local vulnerability (CVSS 8.4); if started with , it becomes remotely exploitable over the network. Dynamic reproduction confirmed command execution as inside a Docker container without any header. ### Details flyto-core exposes an HTTP API via FastAPI. When the API is started ( ), the MCP router is unconditionally mounted at ( ). The route handler at declares with **no** dependency, unlike the analogous REST execution routes ( ) which enforce both authentication and a module denylist. The complete unauthenticated data flow from source to sink: 1. ** ** — is mounted under unconditionally at app creation. 2. ** ** — has no guard; any HTTP client may POST to this route. 3. ** ** — the full request body (attacker-controlled JSON) is parsed without validation. 4. ** ** — each JSON-RPC item is forwarded to without a . 5. ** ** — with name forwards attacker-controlled and to . 6. ** , ** — the module registry resolves and invokes it with attacker-supplied . 7. ** ** — the function wrapper exposes as . 8. ** ** — is read directly from with no sanitization. 9. ** ** — reaches with and no allowlist or escaping. The module is not covered by the default denylist ( at ), so even if were applied it would still be reachable. **Vulnerable code excerpts:** **Contrast with the protected REST route:** The existence of authentication on the REST execution routes demonstrates that a security boundary was intended; the MCP route simply omits it. ### PoC **Environment setup (Docker):** **Exploit (curl) — no Authorization header:** **Exploit (Python PoC script):** **Observed re

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

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  • PyPI flyto-core2.26.2 → 2.26.4
  • vendor FlytoHub Flyto2 Coreversion unspecified

How to fix CVE-2026-55786

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2026-55786 is in the CISA known-exploited catalog. Confirm FlytoHub Flyto2 Core against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with 2.26.2 → 2.26.4. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

CWE-306: Missing Authentication for Critical Function; CWE-78: OS Command Injection. EPSS 0.26%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 14, 2026 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

  2. Oct 14, 2026 · GitHub Advisory Database

    Fix available

    flyto-core fixed in 2.26.4

  3. Oct 14, 2026 · NIST NVD

    Detected

    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 para

  4. Oct 14, 2026 · GitHub Advisory Database

    Fix available

    flyto-core fixed in 2.26.4

Sources

  • CVE.orgVulnerability recordCVE-2026-55786

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-55786

    30-day exploitation probability 0.3%

    first.org
  • GitHub Advisory DatabasePackage advisoryGHSA-h9f9-h6gm-wc85

    GitHub Advisory Database record mirrored by OSV.

    github.com
  • NIST NVDVulnerability recordCVE-2026-55786

    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 u

    nvd.nist.gov
  • OpenSSF OSV / OSV ScannerPackage advisoryGHSA-h9f9-h6gm-wc85

    flyto-core has Unauthenticated Command Execution via HTTP MCP

    osv.dev
  • VulnCheck KEVConfirmed exploitationCVE-2026-55786

    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 u

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.