Description
FastapiAdmin through 3.0 contains a hard-coded JWT signing secret in backend/app/config/setting.py that allows low-privileged users to forge tokens impersonating the superuser. Attackers can register via the unauthenticated /api/v1/system/user/register endpoint, log in, and forge an HS256 token keeping their session_id but naming the superuser in user_name to gain superuser privileges.
References5
- github.com/fastapiadmin/FastapiAdmin/blob/v3.0/backend/app/conf…
- github.com/fastapiadmin/FastapiAdmin/blob/v3.0/backend/app/core…
- hackmd.io/@hieuPenguinnn/fastapiadmin-unauthenticated-autologin…
- www.vulncheck.com/advisories/fastapiadmin-through-3.0-hard-code…
- hackmd.io/@hieuPenguinnn/fastapiadmin-unauthenticated-autologin…
Metrics
- CVSS 3.1
-
8.8
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS 4.0
-
8.7
HIGH
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 30 · as of 10 November 2026
- CWE
- CWE-321
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.