T08 · Insecure Dependencies
- Location
SKILL.md:42- Finding
Unpinned Third-Party Dependency Installation
- Content
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Vulnerability Details
File Location:
SKILL.md, lines 42–46
Vulnerability Type: Unpinned third-party dependency and missing integrity verification
Risk Level: MediumVulnerable Code
markdown ② 安装依赖： ```bash pip install fastmcptext The dependency is subsequently imported by the server at `reg_connector_server.py`, line 26: ```python from fastmcp import FastMCPTechnical Analysis
The installation instructions install
fastmcpwithout a fixed version, cryptographic hashes, a lock file, or an explicitly trusted package index. Consequently, the package and its transitive dependencies are resolved dynamically from the user's configured Python package repository.An unpinned dependency can change after this project has been audited. If the upstream package, one of its transitive dependencies, or the configured package index is compromised, malicious code may execute during package installation or when
fastmcpis imported by the server.Because imported dependency code runs inside the MCP server process, it is not constrained by the otherwise read-only behavior of
reg_connector_server.py. It inherits the server process's operating-system permissions and may access the filesystem, environment variables, credentials available to the process, and network resources.Attack Path
- An attacker compromises a future
fastmcprelease, one of its transitive dependencies, or a package repository used by the victim. - The user follows the documented command
pip install fastmcp. pipresolves and installs the attacker-controlled release because no approved version or artifact hash is specified.- Malicious installation hooks may execute during installation.
- Alternatively, the payload executes when
reg_connector_server.pyimportsfastmcp. - The payload operates with the privileges of the user running the installation or MCP server.
Impact Assessment
Successful exploitation may permit arbitrary code execut ...[truncated 600 chars]
- An attacker compromises a future
- Remediation
View remediation
Remediation Suggestions
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Pin
fastmcpto a specifically reviewed version rather than installing the latest available release:text fastmcp==<reviewed-version> -
Generate a complete lock file covering all transitive dependencies and include SHA-256 hashes for every permitted distribution.
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Document installation using hash enforcement:
bash python -m pip install --require-hashes -r requirements.txt -
Generate locks separately for supported Python versions and platforms where dependency resolution differs.
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Document the expected trusted package index and prevent fallback to untrusted extra indexes.
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Review dependency provenance, release signatures or attestations, maintainers, and transitive dependency changes before updating the lock file.
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Run the MCP server under a dedicated, least-privileged account with restricted filesystem and network access to reduce the impact of a future dependency compromise.
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