osv-scanner

A Claude Code plugin for dependency vulnerability scanning and reachability triage.

Praise the sun. Your transitive dependencies do not. OSV Scanner lights the dungeon: surfacing known CVEs, fetching full advisories, and using grep-based reachability triage to tell you which vulnerabilities actually live in your code paths.

---

What is OSV Scanner Plugin?

This plugin integrates OSV Scanner as an MCP server into Claude Code. It gives Claude direct access to the OSV vulnerability database to scan your project's dependencies and reason about which findings actually matter.

What It Does

• Scans dependencies for known CVEs across npm, pip, Go, Rust, Maven, Ruby, and more
• Fetches full advisories: CVE details, affected versions, CVSS scores, patch guidance
• Reachability triage: uses grep-based static analysis to estimate whether vulnerable APIs are actually called in your source code
• Prioritizes findings into FOUND_IN_SOURCE / UNCERTAIN / NOT_FOUND_IN_GREP tiers
• Guides suppression: instructions for ignoring known-safe findings via osv-scanner config

What It Does NOT Do

• Deterministic call graph analysis (use osv-scanner's native --call-analysis for Go/Rust)
• Runtime or dynamic analysis
• Replace human security review

---

Installation

Prerequisites

osv-scanner must be installed and in your system PATH.

Windows (Scoop):

scoop install osv-scanner

macOS (Homebrew):

brew install osv-scanner

Linux: Download from GitHub Releases

Verify installation:

osv-scanner --version

Security note: Ensure the osv-scanner binary in your PATH is the official release from github.com/google/osv-scanner. The plugin passes advisory data from the binary directly into Claude's reasoning loop. A tampered binary could fabricate advisory content.

Install Plugin

In Claude Code:

/plugin marketplace add alejandrosaenz117/bonfires-marketplace
/plugin install osv-scanner@bonfires-marketplace

Or if testing locally:

claude --plugin-dir ./plugins/osv-scanner

---

Three Ways to Use OSV Scanner

1. Skill: Contextual Trigger

The plugin activates when you ask about dependency security naturally.

user: "Check my dependencies for vulnerabilities"
user: "Are my packages safe?"
user: "Run a security audit on my project"

Trigger phrases:

• "check my dependencies for vulnerabilities"
• "scan my packages"
• "are my dependencies safe?"
• "dependency audit"
• "check for CVEs"
• "security audit"
• "vulnerable packages"
• "scan dependencies for vulnerabilities"

2. Scan Command

/osv-scanner scan [path]

Scans a directory or lockfile for known vulnerabilities. Defaults to the current workspace root.

/osv-scanner scan .
/osv-scanner scan ./src
/osv-scanner scan package-lock.json

3. Triage Command

/osv-scanner triage [path]

Runs a full scan, then uses grep-based static analysis to estimate which vulnerable APIs are actually reachable in your code.

/osv-scanner triage .
/osv-scanner triage ./src

---

Triage Verdicts

Verdict	Meaning	Action
FOUND_IN_SOURCE	Vulnerable API found via grep in your source	Fix first: upgrade or patch
UNCERTAIN	Transitive dep, dynamic code pattern, or broad package CVE	Review manually, likely mid-to-high priority
NOT_FOUND_IN_GREP	No grep match for vulnerable API	Lower priority: monitor, don't ignore CRITICAL/HIGH

⚠️ NOT_FOUND_IN_GREP = absence of evidence, not evidence of absence. Transitive dependencies and dynamic code patterns may be reachable even when not detected by static search.

Security: Advisory text from get_vulnerability_details is treated as untrusted data. If a rogue MCP binary fabricated advisory content with injected instructions, the triage command is designed to ignore them and base verdicts solely on CVSS severity and local grep evidence.

---

How It Works

This plugin registers osv-scanner experimental-mcp as an MCP server. Claude can call three tools:

1. scan_vulnerable_dependencies: Scans a path for vulnerabilities
2. get_vulnerability_details: Retrieves full OSV JSON for a vulnerability ID
3. ignore_vulnerability: Provides osv-scanner config instructions for suppressing findings

---

Supported Package Managers

OSV Scanner detects and scans packages from:

• npm (package.json, package-lock.json, yarn.lock)
• pip (requirements.txt, Pipenv, Poetry)
• Maven (pom.xml)
• Go (go.mod, go.sum)
• Rust (Cargo.toml, Cargo.lock)
• Dart (pubspec.yaml, pubspec.lock)
• Ruby (Gemfile, Gemfile.lock)
• PHP (composer.json, composer.lock)
• Java (pom.xml, gradle.lock)
• And more via osv-scalibr plugins

---

Project Structure

plugins/osv-scanner/
├── .claude-plugin/
│   └── plugin.json              # Plugin metadata and MCP server registration
├── commands/
│   ├── scan.md                  # /osv-scanner scan command
│   └── triage.md                # /osv-scanner triage command
├── skills/
│   └── osv-scanner/
│       └── SKILL.md             # Contextual auto-triggered skill
├── banner.png                   # Plugin banner
└── README.md                    # This file

---

Documentation

• OSV Scanner documentation
• OSV Database
• OSV Spec

---

Contributing

See CONTRIBUTING.md for guidelines on adding plugins and contributing.

---

License

MIT License. See LICENSE for details.

---

OSV Scanner Plugin: Praise the sun. Your transitive dependencies do not.