danny-avila LibreChat up to 0.8.2-rc3 Model Context Protocol OAuth Callback Endpoint missing authentication

Summaryinfo

A vulnerability, which was classified as critical, has been found in danny-avila LibreChat up to 0.8.2-rc3. Impacted is an unknown function of the component Model Context Protocol OAuth Callback Endpoint. This manipulation causes missing authentication. This vulnerability is tracked as CVE-2026-31944. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in danny-avila LibreChat up to 0.8.2-rc3. Affected by this vulnerability is an unknown functionality of the component Model Context Protocol OAuth Callback Endpoint. The manipulation with an unknown input leads to a missing authentication vulnerability. The CWE definition for the vulnerability is CWE-306. The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

LibreChat is a ChatGPT clone with additional features. From 0.8.2 to 0.8.2-rc3, The MCP (Model Context Protocol) OAuth callback endpoint accepts the redirect from the identity provider and stores OAuth tokens for the user who initiated the flow, without verifying that the browser hitting the redirect URL is logged in or that the logged-in user matches the initiator. An attacker can send the authorization URL to a victim; when the victim completes the flow, the victim’s OAuth tokens are stored on the attacker’s LibreChat account, enabling account takeover of the victim’s MCP-linked services (e.g. Atlassian, Outlook). This vulnerability is fixed in 0.8.3-rc1.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-31944 since 03/10/2026. The exploitation appears to be easy. The attack can be launched remotely. Neither technical details nor an exploit are publicly available.

Upgrading to version 0.8.2, 0.8.2-rc3 or 0.8.3-rc1 eliminates this vulnerability.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Chat Software

Vendor

• danny-avila

Name

• LibreChat

Version

• 0.8.2-rc1
• 0.8.2-rc2
• 0.8.2-rc3

Website

• Product: https://github.com/danny-avila/LibreChat/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion