Which versions of Nhost are affected by CVE-2026-34200?

Nhost CLI MCP server versions before 1.41.0 can be exploited by malicious websites to invoke privileged operations using developer credentials when the server is explicitly configured to listen on a…. A patch is available.

How to fix or mitigate CVE-2026-34200?

Within 24 hours: Audit Nhost CLI deployments to identify instances listening on network ports with cross-origin request handling enabled. Within 7 days: Upgrade all affected Nhost CLI installations to version 1.41.0 or later. Within 30 days: Review and enforce default secure configurations across all development environments; document any intentional deviations from default settings and implement compensating network controls.

Nhost CVE-2026-34200

Q: What is the CVSS score of CVE-2026-34200?

CVE-2026-34200 has a CVSS 4.0 base score of 7.7 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.1%.

EUVD-2026-17452 HIGH

Missing Authentication for Critical Function (CWE-306)

2026-03-31 GitHub_M

Authentication Bypass Nhost

7.7

CVSS 4.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

7.7 HIGH

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Scope

Lifecycle Timeline

Analysis Updated

Apr 16, 2026 - 06:10 EUVD-patch-fix

executive_summary

Re-analysis Queued

Apr 16, 2026 - 05:29 backfill_euvd_patch

patch_released

Patch available

Apr 16, 2026 - 05:29 EUVD

1.41.0

EUVD ID Assigned

Mar 31, 2026 - 14:30 euvd

EUVD-2026-17452

Analysis Generated

Mar 31, 2026 - 14:30 vuln.today

CVE Published

Mar 31, 2026 - 13:57 nvd

HIGH 7.7

DescriptionGitHub Advisory

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.

AnalysisAI

Nhost CLI MCP server before version 1.41.0 allows cross-origin requests without authentication when explicitly configured to listen on a network port, enabling malicious websites to invoke privileged tools using developer credentials. The vulnerability requires two explicit non-default configuration steps and does not affect the default configuration, significantly limiting real-world exposure.

Technical ContextAI

The Nhost CLI implements a Model Context Protocol (MCP) server that, when configured to bind to a network interface rather than localhost-only, fails to enforce inbound authentication checks or implement strict Cross-Origin Resource Sharing (CORS) policies. This is a failure of the authentication boundary (CWE-306) where the MCP server trusts requests from cross-origin sources without validating the requestor's identity or authorization. The vulnerability leverages browser same-origin policy bypasses to allow a malicious website to make requests to the local MCP server endpoint on behalf of a developer who has the site open, using the developer's already-authenticated credentials stored in the CLI configuration.

RemediationAI

Upgrade Nhost CLI to version 1.41.0 or later, which implements authentication enforcement and strict CORS validation on the MCP server. For users unable to upgrade immediately, avoid configuring the MCP server to listen on network interfaces; instead use the default localhost-only binding via nhost mcp start without explicit network port configuration. The patch pull request at https://github.com/nhost/nhost/pull/4060 contains implementation details for those requiring additional context.