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Security: yvgude/lean-ctx

SECURITY.md

Security Policy

Reporting a Vulnerability

If you discover a security vulnerability in lean-ctx, please report it privately:

Please do NOT:

  • Open public GitHub issues for security vulnerabilities
  • Disclose vulnerabilities on social media or forums before we've had a chance to address them

What lean-ctx Does (and Doesn't Do)

lean-ctx is a local-only CLI tool and MCP server. Understanding its scope helps assess risk:

Does:

  • Read files from your local filesystem (only files you explicitly request)
  • Execute shell commands (only commands you or your AI tool explicitly invoke)
  • Cache file contents in memory during a session
  • Store statistics in ~/.lean-ctx/stats.json (command counts, token savings)
  • Store session state in ~/.lean-ctx/sessions/ (task context, findings)

Does NOT:

  • Make any network requests or phone home
  • Collect telemetry or usage analytics
  • Access files outside of requested paths
  • Store or transmit credentials, API keys, or secrets
  • Require elevated privileges (runs as your user)

Automated Security Checks

Every push and pull request triggers our CI security pipeline:

  1. cargo audit — Scans dependencies for known CVEs
  2. cargo clippy — Enforces Rust safety lints (warnings = errors)
  3. Dangerous pattern scan — Detects potentially unsafe code patterns:
    • Shell injection vectors (Command::new("sh") with user input)
    • Network operations (reqwest::, std::net::, hyper::)
    • Unsafe code blocks (unsafe {)
    • Environment manipulation (.env("LD_PRELOAD"))
    • Hardcoded secrets or obfuscated strings
  4. cargo test — Full test suite must pass

Critical Files Requiring Enhanced Review

Changes to these files receive extra scrutiny:

File Risk Why
src/shell.rs Shell execution Wraps user's shell, executes commands
src/server.rs MCP protocol Handles all tool calls from AI editors
src/hooks.rs Editor integration Installs hooks into Claude Code, Cursor, etc.
src/core/cache.rs File caching Reads and stores file contents
Cargo.toml Supply chain Dependency manifest
.github/workflows/*.yml CI/CD Release pipeline integrity

Dependency Security

All dependencies in Cargo.toml meet these criteria:

  • Established crates: All 29 dependencies are well-known, widely-used Rust crates
  • License: MIT or Apache-2.0 compatible
  • Active maintenance: Recent commits within 6 months
  • No network crates: lean-ctx has zero HTTP/networking dependencies

Key dependencies and their purpose:

Crate Purpose Downloads
rmcp MCP protocol (stdio transport only) Rust MCP reference impl
tiktoken-rs Token counting (o200k_base) OpenAI's tokenizer
tree-sitter + grammars AST parsing for 18 languages Mozilla's parser
tokio Async runtime (for MCP server) 200M+ downloads
serde / serde_json JSON serialization 400M+ downloads
similar Myers diff algorithm Well-established
walkdir Directory traversal 100M+ downloads

VirusTotal False Positives

Rust binaries are frequently flagged by ML-based antivirus engines (particularly Microsoft Defender's Wacatac.B!ml classifier). This is a known issue affecting many Rust projects:

Why it happens:

  • Statically linked binaries (~30 MB) are unusual for Windows
  • strip = true + lto = true optimizations alter binary structure
  • New/unsigned executables trigger ML classifiers trained on known-good signed software

How to verify lean-ctx yourself:

  1. Build from source: cargo install lean-ctx (compiles on your machine)
  2. Compare SHA256 checksums against our GitHub Releases
  3. Audit the source code: the entire codebase is open source

Build Reproducibility

To verify that a release binary matches the source code:

# Clone and build
git clone https://github.com/yvgude/lean-ctx.git
cd lean-ctx/rust
cargo build --release

# Compare with installed version
lean-ctx --version
./target/release/lean-ctx --version

SHA256 checksums for all release binaries are published in each GitHub Release.


Disclosure Timeline

When vulnerabilities are reported:

  1. Day 0: Acknowledgment sent to reporter
  2. Day 7: Severity assessment completed
  3. Day 14: Patch development begins
  4. Day 30: Patch released + CVE filed (if applicable)
  5. Day 90: Public disclosure

Critical vulnerabilities (RCE, data exfiltration) are fast-tracked.


Contact


Last updated: 2026-03-25

There aren’t any published security advisories