# 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.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Aug 2026
- **Updated:** 21 Aug 2026
- **Also known as:** GHSA-3pvh-63gf-j9mw, PYSEC-2026-3473

## 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 (Improper Neutralization of Special Elements used in a Command)

## Which versions are affected by CVE-2026-54449?

3 open source packages ship an affected version, including langbot.


| Package | Ecosystem | 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.

## Is CVE-2026-54449 being exploited?

There is no known exploitation of CVE-2026-54449 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54449 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-54449 in the wild and no public exploit code.

Affected packages and fixed versions:
- langbot (PyPI): affected all versions up to 4.10.5; no fix listed
- langbot (PyPI): affected all versions up to 4.10.5; no fix listed
- langbot (PyPI): affected all versions up to 4.10.5; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-54449/ (Markdown: https://insights.sbomify.com/CVE-2026-54449/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54449
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54449
- OSV: https://osv.dev/vulnerability/CVE-2026-54449

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54449/
Summaries are generated and may contain mistakes; the official description above is the record.