Vulnerability · Published Aug 20, 2026 · Assigned by GitHub_M
CVE-2026-54449LangBot: Authenticated RCE Via MCP Configuration
High 8.8
In plain English
A high-severity command injection in LangBot from langbot-app. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 54% of all known vulnerabilities).
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | langbot | no fix listed | GHSA-3pvh-63gf-j9mw |
| PyPI | langbot | no fix listed | PYSEC-2026-3473 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| langbot-app | LangBot | <= 4.10.7 |
Weakness: CWE-77 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H