top-web-vulnerabilities

top-web-vulnerabilities is a skill for Claude Code, Codex from zebbern/claude-code-guide. It costs 114 tokens per session (5,251 once invoked), scanned A, original, MIT.

A structured reference to common web-application security vulnerabilities, including their causes, effects, and mitigations. It covers areas such as injection, access control, API security, and configuration mistakes.

In plain words
What is it for?
Use it to study web vulnerabilities, review application or API security, understand common attack categories, and plan fixes using tools such as Burp Suite or OWASP ZAP.
Why use it?
Web security issues are spread across many parts of an application and are easy to overlook. This groups them into a checklist for learning, assessment, and remediation.

Skill for Claude CodeCodex

About the project

Claude Code Guide is a reference collection for configuring and using Claude Code, Anthropic’s command-line coding agent. Developers use it to learn commands, skills, agents, MCP, automation, security, integrations, and troubleshooting. Its catalogue add-ons provide many of the documented skills and agents.

zebbern/claude-code-guide · 4,600 stars · on GitHub

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/zebbern/claude-code-guide/top-web-vulnerabilities
Any agent
npx skills add zebbern/claude-code-guide --skill top-web-vulnerabilities
Clone the repo
git clone --depth 1 https://github.com/zebbern/claude-code-guide

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for top-web-vulnerabilities

README.md
[![agentmods](https://agentmods.dev/badge/skills/zebbern/claude-code-guide/top-web-vulnerabilities.svg)](https://agentmods.dev/skills/zebbern/claude-code-guide/top-web-vulnerabilities)
Your own site
<a href="https://agentmods.dev/skills/zebbern/claude-code-guide/top-web-vulnerabilities"><img src="https://agentmods.dev/badge/skills/zebbern/claude-code-guide/top-web-vulnerabilities.svg" alt="Measured on agentmods" height="20"></a>
Per session 114 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,251 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00114 $0.05251
Opus 5 $0.00057 $0.02625
Sonnet 5 $0.00023 $0.01050
Haiku 4.5 $0.00011 $0.00525

Measured yesterday against content hash f5b61aa17df2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

top-web-vulnerabilities scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

skills/top-web-vulnerabilities/SKILL.md · 544 lines

How it starts

The opening of the file, as written. The whole thing — 544 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Top 100 Web Vulnerabilities Reference

Purpose

Provide a comprehensive, structured reference for the 100 most critical web application vulnerabilities organized by category. This skill enables systematic vulnerability identification, impact assessment, and remediation guidance across the full spectrum of web security threats. Content organized into 15 major vulnerability categories aligned with industry standards and real-world attack patterns.

Prerequisites

  • Basic understanding of web application architecture (client-server model, HTTP protocol)
  • Familiarity with common web technologies (HTML, JavaScript, SQL, XML, APIs)
  • Understanding of authentication and authorization concepts
  • Access to web application security testing tools (Burp Suite, OWASP ZAP)
  • Knowledge of secure coding principles recommended

Outputs and Deliverables

  • Complete vulnerability catalog with definitions, root causes, impacts, and mitigations
  • Category-based vulnerability groupings for systematic assessment
  • Quick reference for security testing and remediation
  • Foundation for vulnerability assessment checklists and security policies

Core Workflow

Phase 1: Injection Vulnerabilities Assessment

Evaluate injection attack vectors targeting data processing components:

SQL Injection (1)

  • Definition: Malicious SQL code inserted into input fields to manipulate database queries
  • Root Cause: Lack of input validation, improper use of parameterized queries
  • Impact: Unauthorized data access, data manipulation, database compromise
  • Mitigation: Use parameterized queries/prepared statements, input validation, least privilege database accounts

Cross-Site Scripting - XSS (2)

  • Definition: Injection of malicious scripts into web pages viewed by other users
  • Root Cause: Insufficient output encoding, lack of input sanitization
  • Impact: Session hijacking, credential theft, website defacement
  • Mitigation: Output encoding, Content Security Policy (CSP), input sanitization

Read the full file on GitHub · 544 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 544 lines · 114 tokens per session scan A f5b61aa17df2

Subscribe to this mod's changes

top-web-vulnerabilities is a skill published in the GitHub repository zebbern/claude-code-guide (4,600 stars, last pushed yesterday), licensed MIT. It adds 114 tokens to every session and 5,251 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.