Missing Authorization in LibreChat - CVE-2026-54027
Published: June 3, 2026
Vulnerability identifier: #VU133262
CSH Severity: Low
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-54027
CWE-ID: CWE-862
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to modify another user's agent resources.
The vulnerability exists due to improper access control in the POST /api/files/images endpoint when handling image upload requests for agent tool_resources. A remote user can upload a file to another user's agent to modify another user's agent resources.
The issue affects uploads where the request targets an agent_id and tool_resource and the upload is processed as a non-message attachment.
Affected software
LibreChat
How to mitigate CVE-2026-54027
Install security update from vendor's website.
LibreChat - update to 0.8.4 rc1