The risk that a model context protocol server, package, or marketplace skill is modified, repackaged, or updated in a way that preserves normal function while changing what it can read or exfiltrate. In identity terms, the danger is that trusted execution inherits user context and becomes a covert data access path.
Expanded Definition
MCP Server Supply Chain Risk describes the possibility that a Model Context Protocol server, connector, package, or marketplace skill is altered before or after deployment so it still appears legitimate while changing the data it can access, observe, or exfiltrate. In practice, this sits at the intersection of software supply chain security and NHI governance because the server often inherits user context, tool permissions, and downstream API access.
Definitions vary across vendors, but the security concern is consistent: trust placed in a signed package, marketplace listing, or dependency path can become a covert data path once the server runs with privileged context. That makes this different from generic malware risk, because the payload may preserve normal function while silently expanding collection behavior. Guidance in the industry is still evolving, so teams should treat every MCP artifact as both code and identity-bearing infrastructure, aligning controls with the OWASP Non-Human Identity Top 10 and the OWASP Agentic AI Top 10.
The most common misapplication is assuming a trusted MCP server cannot become risky after update, which occurs when teams allow package changes, new tool scopes, or marketplace repackaging without revalidating the server’s read and exfiltration paths.
Examples and Use Cases
Implementing MCP supply chain controls rigorously often introduces version pinning, artifact verification, and slower rollout cycles, requiring organisations to weigh deployment speed against the cost of preventing hidden tool abuse.
- A marketplace-hosted MCP server is repackaged with the same name and UI behavior, but quietly adds new file-read permissions that expose prompt history and secrets.
- A dependency update changes a server’s outbound behavior so it forwards retrieved context to an attacker-controlled endpoint while still returning valid responses.
- A build pipeline signs an MCP connector after compilation, but the source repository or post-build artifact is tampered with before publication, creating a trusted distribution channel.
- An internal MCP server is granted broad workspace access, then a minor update introduces a hidden tool that enumerates credentials and metadata from connected systems.
These scenarios mirror patterns seen in NHIMG research such as the Mastra npm Supply Chain Attack — Sapphire Sleet and the JetBrains Marketplace AI Plugin Campaign, where trusted distribution surfaces became the attack path. For implementation baselines, teams can pair that analysis with the NIST Cybersecurity Framework 2.0 and dependency integrity practices discussed in the Analysis of Claude Code Security.
Why It Matters in NHI Security
MCP server compromise is especially dangerous because the server is not just software, it is an active non-human identity with delegated access. Once that identity is abused, the attacker does not need to steal a password to reach data, because the server may already sit inside approved trust boundaries with broad tool permissions and inherited user context.
NHIMG research shows how quickly these trust failures become operationally expensive. In the The State of MCP Server Security 2025 research, 53% of MCP servers exposed credentials through hard-coded configuration values, 24,008 unique secrets were exposed in MCP configuration files in 2025 alone, and only 18% of deployments implemented any form of access scoping for tool permissions. Those numbers make the governance problem concrete, not theoretical, and they reinforce why teams should map this risk to the The State of Secrets in AppSec findings on secret exposure and remediation delay.
Organisations typically encounter the consequence after a credential leak, anomalous tool call, or unexplained data exposure, at which point MCP Server Supply Chain Risk becomes operationally unavoidable to address.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10 and OWASP Agentic AI Top 10 address the attack and risk surface, while NIST CSF 2.0, NIST Zero Trust (SP 800-207) and NIST AI RMF set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-02 | Covers secret exposure and trust abuse in non-human identities. |
| OWASP Agentic AI Top 10 | A2 | Addresses agent tool misuse and supply chain compromise in agentic systems. |
| NIST CSF 2.0 | PR.DS | Protects data flows and integrity of software and services in transit and at rest. |
| NIST Zero Trust (SP 800-207) | AC-4 | Limits data flow and enforces least privilege for trusted components. |
| NIST AI RMF | Reinforces governance, mapping, and monitoring of AI system risks across the lifecycle. |
Inventory MCP servers as AI-adjacent components and monitor them continuously for drift.
