CVE-2026-93559: Jellyfish AI Studio Auth Bypass Vulnerability

CVE-2026-93559 Overview

CVE-2026-93559 is a missing authentication vulnerability [CWE-287] in Forget-C Jellyfish AI Short Drama Studio versions 0.1.0-alpha, 0.2.0, 0.3.0, 0.3.1, and 0.3.2. The flaw resides in an unspecified function within backend/app/dependencies.py, a component of the FastAPI backend. Attackers can exploit the weakness remotely over the network without prior credentials or user interaction. The associated GitHub issue tracking the report was closed automatically due to inactivity, indicating no vendor-supplied patch is currently confirmed.

Critical Impact
Remote, unauthenticated attackers can reach protected functionality exposed by the FastAPI backend, undermining confidentiality, integrity, and availability of the application.

Affected Products

Forget-C Jellyfish AI Short Drama Studio 0.1.0-alpha
Forget-C Jellyfish AI Short Drama Studio 0.2.0
Forget-C Jellyfish AI Short Drama Studio 0.3.0, 0.3.1, and 0.3.2

Discovery Timeline

2026-09-18 - CVE-2026-93559 published to the National Vulnerability Database
2026-09-22 - Last updated in NVD database

Technical Details for CVE-2026-93559

Vulnerability Analysis

The vulnerability affects the dependency-injection layer of the FastAPI backend implemented in backend/app/dependencies.py. FastAPI applications typically enforce authentication through Depends() callables that validate tokens or session state before route handlers execute. In the affected Jellyfish AI Short Drama Studio versions, one or more of these dependency functions do not enforce authentication. Requests reaching protected routes therefore bypass identity verification.

Because the flaw sits at the dependency layer rather than in an individual endpoint, every route relying on the broken dependency inherits the missing check. The result is broad exposure of backend functionality intended for authenticated users only.

Root Cause

The root cause is an authentication control that is either absent, incorrectly implemented, or short-circuited within the shared dependency function. This maps to [CWE-287] Improper Authentication. Downstream handlers trust the dependency's return value as proof of identity, so a missing enforcement path grants callers the same access as an authenticated user.

Attack Vector

Exploitation requires only network reachability to the FastAPI backend. An attacker sends a crafted HTTP request to a route protected by the vulnerable dependency, and the request is processed without credentials. No user interaction, elevated privileges, or specialized tooling is required. The vulnerability carries an EPSS score of 0.654% (49.196 percentile) as of 2026-09-25.

No public exploit code, proof-of-concept, or CISA KEV listing is currently associated with this CVE. See the GitHub Issue Discussion and the VulDB CVE-2026-93559 entry for background.

Detection Methods for CVE-2026-93559

Indicators of Compromise

Successful HTTP 2xx responses from FastAPI routes without a corresponding Authorization, Cookie, or session token header on the request.
Access to backend endpoints from IP addresses that never completed a login or token issuance flow.
Anomalous request volume against /api routes served by the Jellyfish backend, particularly from unauthenticated sources.

Detection Strategies

Inspect application access logs for calls to backend routes that omit authentication headers yet return successful status codes.
Correlate authentication service logs with backend API logs to identify sessions that access resources without a prior authentication event.
Deploy signature and behavioral rules on web application firewalls to flag direct access to sensitive backend/app endpoints without valid tokens.

Monitoring Recommendations

Enable structured request logging in FastAPI with client IP, endpoint, and auth-header presence recorded for every request.
Forward backend logs to a centralized analytics platform and alert on sustained access patterns lacking authentication metadata.
Baseline expected caller identities and alert on new principals or user agents reaching protected endpoints.

How to Mitigate CVE-2026-93559

Immediate Actions Required

Restrict network exposure of the Jellyfish AI Short Drama Studio backend to trusted networks or place it behind an authenticating reverse proxy.
Audit backend/app/dependencies.py for FastAPI Depends() functions that do not raise HTTPException on missing or invalid credentials.
Enumerate every route bound to the affected dependency and treat those endpoints as exposed until compensating controls are in place.

Patch Information

No vendor patch is confirmed at this time. The upstream GitHub issue was closed automatically due to inactivity. Monitor the VulDB entry and the Forget-C Jellyfish repository for a fixed release. Organizations should apply the workarounds below until an official update is available.

Workarounds

Place the FastAPI service behind an authenticating gateway such as an OAuth2 proxy, API gateway, or reverse proxy that enforces token validation before requests reach the backend.
Add network-level access controls (firewall rules, VPN-only exposure, or private subnet placement) to prevent unauthenticated internet access.
Implement a middleware-level authentication check in FastAPI that rejects requests missing valid credentials, providing defense in depth against the broken dependency.

bash

# Example: enforce authentication at a reverse proxy (nginx)
location /api/ {
    auth_request /_auth;
    proxy_pass http://jellyfish_backend;
}

location = /_auth {
    internal;
    proxy_pass http://auth_service/validate;
    proxy_pass_request_body off;
    proxy_set_header Content-Length "";
    proxy_set_header X-Original-URI $request_uri;
}