CVE-2026-61684: Labring Fastgpt

High severity, CVSS 8.8. EPSS: 0.5% chance of exploitation in the next 30 days.

FastGPT is a knowledge-based AI application platform. In 4.15.0-beta4, FastGPT plugin invoke reverse-call endpoints under /api/invoke/* authenticate only by verifying a JWT signed with INVOKE_TOKEN_SECRET, which defaults to the constant string token and was not set in official deployment templates. An unauthenticated attacker can self-sign an HS256 JWT and reach /api/invoke/userInfo to disclose cross-tenant user PII by attacker-supplied tmbId values, or /api/invoke/fileUpload to write attacker-controlled content into chat files. This issue is fixed in version 4.15.0-beta5.

Affected products

• Labring Fastgpt: version 4.15.0-beta4 only

Published 2026-07-15. Last modified 2026-07-15.