CVE-2026-34200 Nhost CLI MCP Server: Missing Inbound Authentication on Explicitly Bound Network Port
Attackers can invoke privileged tools via cross-origin requests if the MCP server is explicitly bound to a network port without authentication.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-34200?
CVE-2026-34200 is a high-severity missing authorization vulnerability in nhost, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Nhost is an open source Firebase alternative with GraphQL. Prior to version 1.41.0, The Nhost CLI MCP server, when explicitly configured to listen on a network port, applies no inbound authentication and does not enforce strict CORS. This allows a malicious website visited on the same machine to issue cross-origin requests to the MCP server and invoke privileged tools using the developer's locally configured credentials. This vulnerability requires two explicit, non-default configuration steps to be exploitable. The default nhost mcp start configuration is not affected. This issue has been patched in version 1.41.0.
Which versions are affected by CVE-2026-34200?
It affects 1 product.
Products include Nhost Cli.
How do I fix CVE-2026-34200?
No fix has been published for CVE-2026-34200 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-34200 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34200 exists.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in nhost
Sources
Also known as GHSA-6c5x-3h35-vvw2.