Auth bypass in Danny-Avila Librechat
CVE-2026-54027
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.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.003 (23.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Danny-Avila Librechat — versions < 0.8.4-rc1
- Librechat
Weakness classification (CWE)
References
- github.com/danny-avila/LibreChat/security/advisories/GHSA-c55r-p24w-hcj5 (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-54027?
- CVE-2026-54027 is a medium-severity vulnerability in Danny-Avila Librechat, classified under Missing Authorization. CVSS score: 6.5/10. Published 2026-06-25.
- How severe is CVE-2026-54027?
- Medium severity. CVSS v3 base score is 6.5 out of 10.