Nhost CLI MCP Server: Missing Inbound Authentication on Explicitly Bound Network Port

published 2026-03-31 7 mo ago modified 2026-07-24 3 mo ago also EUVD-2026-17452

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits: 0; none known

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.

Patch / fix

fixed in 1 links 2

nhost cli 1.41.0

github.com/nhost/nhost@15eae92 commit
github.com/nhost/nhost#4060 pull request

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 7 mo ago (2026-03-31)

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/nhost/nhost/security/advisories/GHSA-6c5x-3h35-vvw2 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	7.7	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
CNA	4.0	7.7	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
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

nhost nhost

Classification

Weakness

CWE-306 Missing Authentication for Critical Functionality
CWE-942 Permissive Cross-domain Security Policy with Untrusted Domains

References

github.com /nhost/nhost/pull/4060
issue-tracking, patch
github.com /nhost/nhost/commit/15eae9285f9dce63e184b9bb24616474ffa5ccc9
patch
github.com /nhost/nhost/security/advisories/GHSA-6c5x-3h35-vvw2
exploit, vendor-advisory

Sources

CVE List CVE-2026-34200
NVD CVE-2026-34200

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary