Raw 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:XSummary
CVE-2026-34200 is a high-severity Missing Authentication for Critical Function (CWE-306) vulnerability in Nhost Cli. Its CVSS base score is 7.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 29th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
This vulnerability is AI-related — categorised as AI Agent Protocols and Integrations; in the Protocol-Specific Risks risk domain.
The strongest mitigations our analysis identified map to AC-14 (Permitted Actions Without Identification or Authentication) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-34200 is a vulnerability in the Nhost CLI MCP server, part of Nhost, an open-source Firebase alternative with GraphQL support. In versions prior to 1.41.0, the MCP server, when explicitly configured to listen on a network port, implements no inbound authentication and fails to enforce strict CORS policies. This exposes the server to unauthorized cross-origin requests from web contexts on the same host machine.
The vulnerability can be exploited by an attacker who tricks a developer into visiting a malicious website while the MCP server is running with the vulnerable configuration. No attacker privileges are required (PR:N), but exploitation demands network access (AV:N), high attack complexity (AC:H), and user interaction (UI:R) via the malicious site. Successful exploitation allows the attacker to issue cross-origin requests to the MCP server, invoking privileged tools using the developer's locally configured credentials, potentially leading to high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H, CVSS 3.1 score of 7.5). It requires two explicit, non-default configuration steps, and the default "nhost mcp start" setup is unaffected.
Mitigation is available in Nhost version 1.41.0, which patches the authentication and CORS issues. The Nhost security advisory (GHSA-6c5x-3h35-vvw2) and associated GitHub pull request (#4060) and commit (15eae9285f9dce63e184b9bb24616474ffa5ccc9) detail the fix. Practitioners should upgrade to 1.41.0 or later and avoid non-default network-binding configurations for the MCP server.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-17452
Vulnerability Data
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…
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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.
- CWE(s)
AI Security AnalysisAI
- AI Category
- AI Agent Protocols and Integrations
- Risk Domain
- Protocol-Specific Risks
- OWASP Top 10 for LLMs 2025
- None mapped
- Classification Reason
- Matched keywords: mcp
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 6 hardening rules · 3 OS baselines
V3.4.3V3.4.6V6.2.3V6.4.4
Mitigating Controls (NIST 800-53 r5) AI
Directly mandates unique identification and authentication of users before access to functions requiring identity.
Extends the same authentication requirement to non-organizational users accessing critical functionality.
Requires authentication of services before they can invoke or expose critical functions.
Explicitly identifies and limits actions permitted without authentication, preventing critical functions from being exposed.
Information flow enforcement requires approved authorizations and would reject policies permitting untrusted domains.
Access enforcement requires prior authentication before any authorization decision for critical functions.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Directly requires authentication of users/services/hardware, which eliminates missing authentication for critical functions.
Hardened configuration baselines and reviews directly prevent permissive CSP or cross-domain policies.
Secure SDLC activities include review and testing of web security policies to avoid untrusted domains.
Vulnerability identification processes can surface permissive policy misconfigurations.
Managing identities and credentials is a prerequisite for authentication but does not itself enforce it on critical functions.
Defining and enforcing authorizations assumes prior authentication and therefore only partially mitigates the absence of authentication.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
The control explicitly calls for authentication before any critical function is reached, eliminating the possibility of bypassing authentication for high-value operations.
Security testing can detect overly permissive cross-domain policies but does not prevent their initial introduction.
Mandating authentication requirements for critical functions at the requirements-gathering stage ensures that essential operations are not left unprotected by missing login or verification mechanisms.
Network security policies can restrict cross-domain communication but do not specifically mandate strict CSP or cross-domain policy configuration.
Mandating authentication for network services and critical functions stops attackers from invoking sensitive operations without credentials, closing gaps where authentication is absent for important capabilities.
Web filtering can block untrusted domains at the network level, partially mitigating permissive cross-domain policies.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (2 rules)
- V-248585 OL 8 must require reauthentication when using the "sudo" command. prevents CWE-306
- V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-306
RHEL 7 (2 rules)
- V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-306
- V-237635 The Red Hat Enterprise Linux operating system must require re-authentication when using the "sudo" command. prevents CWE-306
RHEL 8 (2 rules)
- V-230492 RHEL 8 must not have the rsh-server package installed. prevents CWE-306
- V-237643 RHEL 8 must require re-authentication when using the "sudo" command. prevents CWE-306