⭐ If this plugin caught a real bug for you, star the repo — it's the signal that keeps these rules maintained.

Description

This plugin provides Security validation for JSON Web Tokens (JWT) implementation (signing, verification).

Philosophy

Interlace fosters strength through integration. Instead of stacking isolated rules, we interlace security directly into your workflow to create a resilient fabric of code. We believe tools should guide rather than gatekeep, providing educational feedback that strengthens the developer with every interaction.

Why these rules are quiet

Noise creates apathy, and apathy is not a security posture. A linter that reports a thousand things a week gets switched off in a month, and the real finding goes with it. So every rule here is built to be worth reading: we would rather miss a finding than spend your attention on one that was never real.

That is a trade, and it is made deliberately. It costs recall, and we measure what it costs rather than assuming it is free.

How the rules decide

Evidence, not names. A rule fires on what the code does, resolved through the AST and ESLint's own scope analysis — not on an identifier that happens to contain query, a method called setItem, or a file whose path contains key. Every one of those was a real false positive in this ecosystem, found by reading our own output on open-source projects and fixed with a test that fails on the unfixed rule.

Where a rule has known false-positive shapes, its page carries a Not a finding section: what it deliberately stays quiet on, and what to check first when it fires and you disagree.

What you get

The rules below. Security rules carry a CWE mapping and, where one is assigned, a CVSS score; every rule carries a fix on its message — in prose for a human and as structured JSON for an agent. Install it, enable recommended, and read the findings. If one of them is wrong, open an issue — a false positive is a bug here, not a tuning exercise for you.

How that is measured, on which projects, and where it falls short: benchmark methodology and results.

Getting Started

• To check out the guide, visit eslint.interlace.tools. 📚
• 要查看中文 指南, 请访问 eslint.interlace.tools. 📚
• 가이드 문서는 eslint.interlace.tools에서 확인하실 수 있습니다. 📚
• ガイドは eslint.interlace.toolsでご確認ください。 📚
• Para ver la guía, visita eslint.interlace.tools. 📚
• للاطلاع على الدليل، قم بزيارة eslint.interlace.tools. 📚

npm install eslint-plugin-jwt-security --save-dev

⚙️ Configuration Presets

| Preset | Description | | :------------ | :-------------------------------------------------------- | | recommended | Recommended preset - balanced security | | strict | Strict preset - maximum security (includes 2025 research) | | legacy | Legacy preset - migration mode | | all | All rules preset |

📚 Supported Libraries

| Library | npm | Downloads | Detection | | :------------- | :-------------------------------------------------------------------------------------------------------------------- | :--------------------------------------------------------------------------------------------------------------------------- | :------------------------------ | | jsonwebtoken | | | Signing, Verification, Decoding | | jose | | | Verification (Fix Suggestion) | | jwt-decode | | | Unsafe Decoding |

🤖 AI-Optimized Messages

Every rule uses formatLLMMessage for structured output:

🔒 CWE-347 OWASP:A02-Crypto CVSS:9.8 | Using alg:"none" bypasses signature verification
   Fix: Remove "none" and use RS256, ES256, or other secure algorithms
   https://nvd.nist.gov/vuln/detail/CVE-2022-23540

By providing this structured context (CWE, OWASP, Fix), we enable AI tools to reason about the security flaw rather than hallucinating. This allows Copilot/Cursor to suggest the exact correct fix immediately.

By structuring errors with specific CWE codes, OWASP categories, and direct fix suggestions, this format allows AI coding assistants to autonomously identify, explain, and resolve security vulnerabilities with high confidence.

💡 What You Get

• 13 Security Rules - Algorithm attacks, replay prevention, claim validation
• 6 JWT Libraries - jsonwebtoken, jose, express-jwt, @nestjs/jwt, jwks-rsa, jwt-decode
• 2025 Research - "Back to the Future" replay attack prevention (LightSEC 2025)
• AI-Optimized - Structured messages for GitHub Copilot, Cursor, Claude assistance
• CWE References - Every rule maps to Common Weakness Enumeration

📦 Compatibility

| Package | Version | | :--- | :--- | | ESLint | ^8.40.0 \|\| ^9.0.0 \|\| ^10.0.0 | | Node.js | >=18.0.0 |

See the ESLint Version Support Policy — current ecosystem share data, the 20% gate, and the forward-looking exception that covers v10.

Rules

Legend

| Icon | Description | | :---: | :--- | | 💼 | Recommended: Included in the recommended preset. | | ⚠️ | Warns: Set to warn in recommended preset. | | 🔧 | Auto-fixable: Automatically fixable by the --fix CLI option. | | 💡 | Suggestions: Providing code suggestions in IDE. | | 🚫 | Deprecated: This rule is deprecated. | | 🟢 | Type-unaware: AST-only, runs in oxlint JS-plugin tier. | | 🟡 | Type-aware (refining): pure-AST primary path; types refine precision. | | 🟠 | Type-aware (graceful): requires TS program; silent without it. |

| Rule | CWE | OWASP | CVSS | Description | 🧠 | 💼 | ⚠️ | 🔧 | 💡 | 🚫 | | :--- | :---: | :---: | :---: | :--- | :---: | :---: | :---: | :---: | :---: | :---: | | no-algorithm-confusion | CWE-347 | | | This rule detects algorithm confusion attacks where symmetric algorithms (HS256, HS384, HS512) are used wit… | 🟢 | 💼 | | | | | | no-algorithm-none | CWE-347 | | | This rule detects attempts to use the none algorithm which completely bypasses JWT signature verification | 🟢 | 💼 | | | | | | no-decode-without-verify | CWE-345 | | | The rule provides LLM-optimized error messages (Compact 2-line format) with actionable security guidance: | 🟢 | 💼 | | | | | | no-hardcoded-secret | CWE-798 | | | The rule provides LLM-optimized error messages (Compact 2-line format) with actionable security guidance: | 🟢 | 💼 | | | | | | no-sensitive-payload | CWE-359 | | | JWT payloads are NOT encrypted, only base64-encoded | 🟢 | | ⚠️ | | | | | no-timestamp-manipulation | CWE-294 | | | This rule detects noTimestamp: true which disables automatic iat (issued at) claim generation | 🟢 | 💼 | | | | | | no-weak-secret | CWE-326 | | | The rule provides LLM-optimized error messages (Compact 2-line format) with actionable security guidance: | 🟢 | 💼 | | | | | | require-algorithm-whitelist | CWE-757 | | | This rule enforces explicit algorithm specification in verify() calls | 🟢 | 💼 | | | | | | require-audience-validation | CWE-287 | | | The rule provides LLM-optimized error messages (Compact 2-line format) with actionable security guidance: | 🟢 | | | | | | | require-expiration | CWE-613 | | | The rule provides LLM-optimized error messages (Compact 2-line format) with actionable security guidance: | 🟢 | 💼 | | | | | | require-issued-at | CWE-294 | | | This rule ensures tokens have the iat claim for freshness validation | 🟢 | | | | | | | require-issuer-validation | CWE-287 | | | The rule provides LLM-optimized error messages (Compact 2-line format) with actionable security guidance: | 🟢 | | | | | | | require-max-age | CWE-294 | | | This rule mandates maxAge in verify operations | 🟢 | | | | | |

🔗 Related ESLint Plugins

Part of the Interlace ESLint Ecosystem — AI-native security plugins with LLM-optimized error messages:

| Plugin | Downloads | Description | | :--- | :---: | :--- | | eslint-plugin-secure-coding | | General security rules & OWASP guidelines. | | eslint-plugin-pg | | PostgreSQL security & best practices. | | eslint-plugin-node-security | | Node.js core-module security (fs, child_process, vm, crypto, Buffer). | | eslint-plugin-jwt-security | | JWT security & best practices. | | eslint-plugin-browser-security | | Browser-specific security & XSS prevention. | | eslint-plugin-express-security | | Express.js security hardening rules. | | eslint-plugin-lambda-security | | AWS Lambda security best practices. | | eslint-plugin-nestjs-security | | NestJS security rules & patterns. | | eslint-plugin-mongodb-security | | MongoDB security best practices. | | eslint-plugin-vercel-ai-security | | Vercel AI SDK security hardening. | | eslint-plugin-import-next | | Next-gen import sorting & architecture. |

⭐ Support & follow

If this plugin caught a real bug for you, star the repo — stars are the signal that keeps the Interlace ESLint ecosystem maintained — and follow the writeups on Dev.to for the benchmarks and security research behind these rules.

📄 License

MIT © Ofri Peretz