LangBot: Authenticated RCE Via MCP Configuration (CVE-2026-54449) | HOL Guard CVE

High · CVSS 8.8CVE-2026-54449GHSA-3PVH-63GF-J9MW

LangBot: Authenticated RCE Via MCP Configuration

Answer in brief

CVE-2026-54449 records a High severity (CVSS 8.8) vulnerability in LangBot: Authenticated RCE Via MCP Configuration. The current sources do not mark it as known exploited. The current feed maps langbot-app/LangBot (generic), langbot (pip). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 20, 2026Updated Aug 21, 2026Source checked Sep 17, 2026First seen by HOL Jul 15, 2026Material review Aug 21, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.8
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Not reported

Why this deserves its current priority

CVSS is 8.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps langbot-app/LangBot (generic), langbot (pip). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
langbot-app/LangBotgeneric	<= 4.10.7	Not reported
langbotpip	<=4.10.5	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for langbot-app/LangBot, langbot.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Aug 20, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jul 15, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.