Auth bypass in Nhost Cli
CVE-2026-34200
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.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.006 (48.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/nhost/nhost/security/advisories/GHSA-6c5x-3h35-vvw2 (Exploit, Vendor Advisory)
- github.com/nhost/nhost/pull/4060 (Patch, Issue Tracking)
- github.com/nhost/nhost/commit/15eae9285f9dce63e184b9bb24616474ffa5ccc9 (Patch)
Frequently asked questions
- What is CVE-2026-34200?
- CVE-2026-34200 is a high-severity vulnerability in Nhost Cli, classified under Missing Authentication for Critical Function. CVSS score: 7.5/10. Published 2026-03-31.
- How severe is CVE-2026-34200?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2026-34200 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.