SB2026060302 - Multiple vulnerabilities in LibreChat
Published: June 3, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 vulnerabilities.
1) Improper access control (CVE-ID: N/A)
CWE-ID: CWE-284 - Improper Access Control
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to improper access control in packages/api/src/mcp/oauth/handler.ts when processing OAuth protected resource metadata from an MCP server. A remote attacker can supply crafted metadata with a mismatched resource parameter to disclose sensitive information.
User interaction is required to complete the OAuth flow.
2) Incorrect authorization (CVE-ID: CVE-2026-44654)
CWE-ID: CWE-863 - Incorrect Authorization
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to improper access control in the /api/files DELETE endpoint when handling file deletion requests for shared agents. A remote user can delete a reused file record by file_id to cause a denial of service.
The issue affects files reused across multiple agents, leaving other agents with stale file_id references that no longer resolve.
Remediation
Install update from vendor's website.