VulnerabilityReceived

CVE-2026-54449

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.

HIGH 8.8EPSS 0.41%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.41%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.1: 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.41% probability · 35th percentile
CISA KEV: Not listed
Weakness: CWE-77
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.