CVE-2026-40252: Broken Access Control (IDOR) Leading to Cross-Tenant Application Access in FastGPT

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-10 · updated 2026-10-26
Weakness: CWE-284

Description

FastGPT is an AI Agent building platform. Prior to 4.14.10.4, Broken Access Control vulnerability (IDOR/BOLA) allows any authenticated team to access and execute applications belonging to other teams by supplying a foreign appId. While the API correctly validates the team token, it does not verify that the requested application belongs to the authenticated team. This leads to cross-tenant data exposure and unauthorized execution of private AI workflows. This vulnerability is fixed in 4.14.10.4.

Affected products

labring FastGPT: before 4.14.10.4 — fixed in 4.14.10.4

How to fix

Upgrade to a fixed version: labring FastGPT 4.14.10.4. Check the vendor advisory for mitigations.

References

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