xss-prevention SKILL.md skillA
xss-prevention from secondsky/claude-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add secondsky/claude-skills/xss-prevention@git:20260719.059fc9fPins git:20260719.059fc9f in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- secondsky/claude-skills
- Path
plugins/xss-prevention/skills/xss-prevention/SKILL.md- Versions recorded
- 4
- Latest version
- git:20260719.059fc9f, committed Jul 19, 2026
- First version recorded
- Dec 24, 2025
- Size
- 6,054 bytes
- Repository stars
- 247
- License
- MIT
XSS attack prevention with input sanitization, output encoding, Content Security Policy. Use for user-generated content, rich text editors, web application security, or encountering stored XSS, reflected XSS, DOM manipulation, script injection errors.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# XSS Prevention
## Overview
Implement comprehensive Cross-Site Scripting attack prevention through input sanitization, output encoding, Content Security Policy headers, and secure coding practices.
## When to Use
- User-generated content display
- Rich text editors
- Comment systems
- Search functionality
- Dynamic HTML generation
- Template rendering scenarios
## XSS Attack Types
| Type | Vector | Defense |
|------|--------|---------|
| Reflected | URL parameters | Output encoding |
| Stored | Database content | Input sanitization |
| DOM-based | Client-side JS | Safe DOM APIs |
| Mutation | HTML parser quirks | Strict sanitization |
## Output Encoding (Node.js)
```javascript
function encodeHTML(str) {
return str
.replace(/&/g, '&')
.replace(/</g, '<')
.replace(/>/g, '>')
.replace(/"/g, '"')
.replace(/'/g, ''');
}
function encodeForAttribute(str) {
return str.replace(/[^\w.-]/g, char =>
`&#x${char.charCodeAt(0).toString(16)};`
);
}
// Usage in templates
app.get('/profile', (req, res) => {
const username = encodeHTML(req.query.name);
res.send(`<h1>Welcome, ${username}</h1>`);
});
```
## DOMPurify Sanitization
…Read the whole file at its exact version.
How to install
mdr add secondsky/claude-skills/xss-prevention@sha256:dba321ea23e8a18eThe line at the top of this page pins the label git:20260719.059fc9f, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_mardqotvgcnjtfj6)
4 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 4 versions of this file, between Dec 24, 2025 and Jul 19, 2026, about one every 69 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260719.059fc9f latest | 2026-07-19 | 059fc9f | 6,054 B | A | view · diff |
| git:20260429.5f7b93b | 2026-04-29 | 5f7b93b | 5,750 B | A | view · diff |
| git:20260426.852a9f7 | 2026-04-26 | 852a9f7 | 5,639 B | A | view · diff |
| git:20251224.ba827ce | 2025-12-24 | ba827ce | 5,632 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (6054 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
secondsky/claude-skills · 247 stars · license MIT · pushed 2026-10-31 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_mardqotvgcnjtfj6 GET https://markdownregistry.com/api/v1/resolve?ref=secondsky/claude-skills/xss-prevention GET https://markdownregistry.com/api/v1/blob/dba321ea23e8a18ef4d0c647f028a79186d18494ed0ed4f9890df8e4ac08b283
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.