CVE-2026-54449 HIGH

CVE-2026-54449: LangBot: Authenticated RCE Via MCP Configuration

Vendor Langbot-App
Product LangBot
Weakness CWE-77
Published August 20, 2026
Last update August 21, 2026

CVSS base score

8.8/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

What the vulnerability does

01Description

LangBot is a global IM bot platform designed for LLMs. In version 4.10.7 and earlier, any authenticated user can add or change an STDIO MCP server configuration without an adequate authorization boundary. In src/langbot/pkg/provider/tools/loaders/mcp.py, StdioServerParameters accepts the configured command and arguments and starts a server-side subprocess on the LangBot server. An attacker who can sign up or obtain an account can use the Extensions MCP configuration to execute arbitrary commands with the privileges of the LangBot service, enabling data disclosure, modification, and service disruption. No fixed version is available as of this review.

Key dates

02Disclosure timeline

August 20, 2026 CVE published
August 21, 2026 Record updated

Related vulnerabilities

04Related CVE