CVE-2026-55786 flytohub CVE debrief

Who should care

Defenders responsible for flyto-core instances, especially those in network-exposed deployments, should assess exposure and prioritize upgrading to version 2.26.4 or later. They should also verify if flyto-core instances are running with the default binding to 127.0.0.1 or if they are exposed to the network by binding to 0.0.0.0. Additionally, defenders should monitor for suspicious activity on the HTTP MCP endpoint and review compensating controls for

Why it matters

CVE-2026-55786 allows unauthenticated command execution in flyto-core, posing a high-severity risk for local exploitation and potentially remote exploitation if improperly configured. Defenders should verify exposure, prioritize upgrading to version 2.26.4 or later, and monitor for suspicious activity.

• Unauthenticated command execution as the flyto-core server process.
• Potential for remote exploitation if flyto-core is started with --host 0.0.0.0.
• Need for verification of affected versions and exposure.

Technical summary

The HTTP MCP endpoint in flyto-core accepts unauthenticated JSON-RPC requests and dispatches them to arbitrary registered modules, allowing an unauthenticated attacker to execute arbitrary OS commands as the flyto-core server process. This vulnerability can be exploited locally, with a CVSS score of 8.4, and potentially remotely if flyto-core is started with --host 0.0.0.0. The vulnerability is confirmed to be exploitable via dynamic reproduction inside a Docker container without any Authorization header. The root cause of the vulnerability lies in the unsecured JSON-RPC interface, which allows arbitrary command execution.

Defensive priority

Defenders should prioritize verifying exposure of flyto-core instances, especially those binding to 0.0.0.0, and upgrading to version 2.26.4 or later.

Recommended defensive actions

• Verify if flyto-core instances are running with the default binding to 127.0.0.1 or if they are exposed to the network by binding to 0.0.0.0.
• Check if the flyto-core version is 2.26.2 or 2.26.3 and upgrade to version 2.26.4 or later.
• Monitor for suspicious activity on the HTTP MCP endpoint.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Evidence notes

The source corpus confirms unauthenticated command execution via the HTTP MCP endpoint in flyto-core, with dynamic reproduction inside a Docker container. However, details on affected versions and remediation are limited.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.