Writing Custom Semgrep Rules to Catch Solana Anchor Vulnerabilities Before Auditors Do

Writing Custom Semgrep Rules to Catch Solana Anchor Vulnerabilities Before Auditors Do You've written your Anchor program. It compiles. Tests pass. You're ready to deploy. But buried in your instruction handlers are patterns that every experienced auditor knows to look for — and that automated tools regularly miss. Missing signer checks. Unconstrained account deserialization. Authority fields that nobody validates. Here's the thing: you don't need to wait for a $50K audit to find these. With Semgrep — a lightweight static analysis tool — you can write custom rules that catch the most common Anchor vulnerabilities in seconds. This guide walks through building a practical Semgrep ruleset for Solana Anchor programs. Every rule targets a real vulnerability class that has led to actual exploits. Why Semgrep for Solana? The Solana security tooling landscape in 2026 looks like this: Tool Strength Weakness cargo-audit Known CVEs in dependencies Zero coverage of logic bugs Soteria Solana-specif