CVE-2026-54027 LibreChat: Image Upload Route Bypasses Agent Permission Check — Incomplete Fix for File Upload Authorization

Medium 6.5 Published 25 Jun 2026 Updated 26 Jun 2026

Authenticated users can upload files to any agent's resources without proper permission checks, allowing unauthorized modification of agent contexts.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-54027?

CVE-2026-54027 is a medium-severity missing authorization vulnerability in Librechat Librechat, published on 25 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

LibreChat is an enhanced ChatGPT clone that supports multiple AI providers. Prior to 0.8.4-rc1, the POST /api/files/images endpoint allows any authenticated user to upload files into any agent's tool_resources (e.g., context, execute_code) without verifying ownership or EDIT permission on the target agent. A permission check was added to the POST /api/files route in a previous patch, but the image upload route was never updated with the same check. An attacker can simply use the image endpoint instead of the file endpoint to bypass the authorization entirely. This vulnerability is fixed in 0.8.4-rc1.

Weakness: CWE-862

Which versions are affected by CVE-2026-54027?

It affects 1 product.

Products include Librechat Librechat.

How do I fix CVE-2026-54027?

No fix has been published for CVE-2026-54027 yet. Limit exposure of the affected software until one is available.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-54027 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54027 exists.

All Librechat Librechat vulnerabilities

Sources

Also known as GHSA-c55r-p24w-hcj5.