CVE-2026-61684 FastGPT: Unauthenticated cross-tenant data access via forgeable plugin-invoke JWT (default INVOKE_TOKEN_SECRET='token')
Unauthenticated attackers can forge JWTs using a default hardcoded secret to access cross-tenant user data and upload files in FastGPT.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-61684?
CVE-2026-61684 is a high-severity vulnerability in labring FastGPT, published on 15 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-798
Which versions are affected by CVE-2026-61684?
How do I fix CVE-2026-61684?
No fix has been published for CVE-2026-61684 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-61684 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61684 exists.
Sources
Also known as GHSA-w732-rq8c-chc8.