CVE-2026-54449 LangBot: Authenticated RCE Via MCP Configuration
Authenticated users can execute arbitrary commands on the LangBot server by manipulating MCP configuration, leading to full system compromise.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-54449?
CVE-2026-54449 is a high-severity command injection vulnerability in langbot-app LangBot, published on 20 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
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.
Weakness: CWE-77
Which versions are affected by CVE-2026-54449?
3 open source packages ship an affected version, including langbot.
| Package | Affected | Fixed in |
|---|---|---|
langbot PyPI | All versions to 4.10.5 | None |
langbot PyPI | All versions to 4.10.5 | None |
langbot PyPI | All versions to 4.10.5 | None |
How do I fix CVE-2026-54449?
No fix has been published for CVE-2026-54449 yet. Limit exposure of the affected software until one is available.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-54449 being exploited?
There is no known exploitation of CVE-2026-54449 in the wild and no public exploit code.
Sources
Also known as GHSA-3pvh-63gf-j9mw, PYSEC-2026-3473.