CVE-2026-40252 labring CVE debrief

Who should care

Defenders responsible for AI Agent building platforms, specifically those using FastGPT, should assess their exposure and verify the patch has been applied. This vulnerability may impact teams with access to sensitive AI workflows and applications.

Why it matters

The CVE-2026-40252 vulnerability in FastGPT allows unauthorized access and execution of private AI workflows due to a Broken Access Control issue. Defenders should prioritize verifying and applying the patch (version 4.14.10.4) to prevent potential exploitation and data exposure.

• Potential unauthorized access to sensitive AI workflows and applications.
• Possible execution of private AI workflows by unauthorized teams.
• Cross-tenant data exposure due to inadequate access controls.
• Verification of patch application and access controls is necessary to prevent exploitation.

Technical summary

The FastGPT platform, prior to version 4.14.10.4, contains a Broken Access Control vulnerability (IDOR/BOLA) that allows any authenticated team to access and execute applications belonging to other teams by supplying a foreign appId. The API correctly validates the team token but fails to verify that the requested application belongs to the authenticated team, leading to cross-tenant data exposure and unauthorized execution of private AI workflows.

Defensive priority

Defenders should prioritize verifying and applying the patch (version 4.14.10.4) to prevent unauthorized access and execution of private AI workflows.

Recommended defensive actions

• Verify and apply the patch (version 4.14.10.4) to prevent unauthorized access and execution of private AI workflows.
• Restrict access to sensitive AI workflows and applications.
• Monitor for suspicious activity and implement additional security measures to detect potential exploitation.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record and NVD entry provide details on the Broken Access Control vulnerability in FastGPT, which allows any authenticated team to access and execute applications belonging to other teams. The vulnerability is fixed in version 4.14.10.4.

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.