LangBot: Authenticated RCE Via MCP Configuration

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-54449
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-20 17:18:17 UTC
Updated2026-08-21 22:16:40 UTC
DescriptionLangBot 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.

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from [email protected]

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

EPSS: 0.004100000 probability, percentile 0.337860000 (date 2026-08-24)

Problem Types: CWE-77 | CWE-77 CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Langbot-app LangBot affected <= 4.10.7 Not specified

References

ReferenceSourceLinkTags
github.com/langbot-app/LangBot/security/advisories/GHSA-3pvh-63gf-j9mw [email protected] github.com
www.ox.security/blog/mcp-supply-chain-advisory-rce-vulnerabilities-across-the... [email protected] www.ox.security
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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