XSS Vulnerability Scanner for Frontend Code

Overview

This public intake copy packages

plugins/antigravity-awesome-skills-claude/skills/frontend-mobile-security-xss-scan

https://github.com/sickn33/antigravity-awesome-skills

Use it when the operator needs the upstream workflow, support files, and repository context to stay intact while the public validator and private enhancer continue their normal downstream flow.

This intake keeps the copied upstream files intact and uses

metadata.json

ORIGIN.md

XSS Vulnerability Scanner for Frontend Code You are a frontend security specialist focusing on Cross-Site Scripting (XSS) vulnerability detection and prevention. Analyze React, Vue, Angular, and vanilla JavaScript code to identify injection points, unsafe DOM manipulation, and improper sanitization.

Imported source sections that did not map cleanly to the public headings are still preserved below or in the support files. Notable imported sections: Context, Requirements, Output Format, Limitations.

When to Use This Skill

Use this section as the trigger filter. It should make the activation boundary explicit before the operator loads files, runs commands, or opens a pull request.

• Working on xss vulnerability scanner for frontend code tasks or workflows
• Needing guidance, best practices, or checklists for xss vulnerability scanner for frontend code
• The task is unrelated to xss vulnerability scanner for frontend code
• You need a different domain or tool outside this scope
• Use when the request clearly matches the imported source intent: You are a frontend security specialist focusing on Cross-Site Scripting (XSS) vulnerability detection and prevention. Analyze React, Vue, Angular, and vanilla JavaScript code to identify injection poi.
• Use when the operator should preserve upstream workflow detail instead of rewriting the process from scratch.

Operating Table

metadata.json

ORIGIN.md

SKILL.md

SKILL.md

## Related Skills

Workflow

This workflow is intentionally editorial and operational at the same time. It keeps the imported source useful to the operator while still satisfying the public intake standards that feed the downstream enhancer flow.

1. Never use innerHTML with user input
2. Prefer textContent for text content
3. Sanitize with DOMPurify before rendering HTML
4. Avoid document.write entirely
5. Validate all URLs before assignment
6. Block javascript: and data: protocols
7. Use URL constructor for validation

Imported Workflow Notes

Imported: Instructions

1. XSS Vulnerability Detection

Scan codebase for XSS vulnerabilities using static analysis:

interface XSSFinding {
  file: string;
  line: number;
  severity: 'critical' | 'high' | 'medium' | 'low';
  type: string;
  vulnerable_code: string;
  description: string;
  fix: string;
  cwe: string;
}

class XSSScanner {
  private vulnerablePatterns = [
    'innerHTML', 'outerHTML', 'document.write',
    'insertAdjacentHTML', 'location.href', 'window.open'
  ];

  async scanDirectory(path: string): Promise<XSSFinding[]> {
    const files = await this.findJavaScriptFiles(path);
    const findings: XSSFinding[] = [];

    for (const file of files) {
      const content = await fs.readFile(file, 'utf-8');
      findings.push(...this.scanFile(file, content));
    }

    return findings;
  }

  scanFile(filePath: string, content: string): XSSFinding[] {
    const findings: XSSFinding[] = [];

    findings.push(...this.detectHTMLManipulation(filePath, content));
    findings.push(...this.detectReactVulnerabilities(filePath, content));
    findings.push(...this.detectURLVulnerabilities(filePath, content));
    findings.push(...this.detectEventHandlerIssues(filePath, content));

    return findings;
  }

  detectHTMLManipulation(file: string, content: string): XSSFinding[] {
    const findings: XSSFinding[] = [];
    const lines = content.split('\n');

    lines.forEach((line, index) => {
      if (line.includes('innerHTML') && this.hasUserInput(line)) {
        findings.push({
          file,
          line: index + 1,
          severity: 'critical',
          type: 'Unsafe HTML manipulation',
          vulnerable_code: line.trim(),
          description: 'User-controlled data in HTML manipulation creates XSS risk',
          fix: 'Use textContent for plain text or sanitize with DOMPurify library',
          cwe: 'CWE-79'
        });
      }
    });

    return findings;
  }

  detectReactVulnerabilities(file: string, content: string): XSSFinding[] {
    const findings: XSSFinding[] = [];
    const lines = content.split('\n');

    lines.forEach((line, index) => {
      if (line.includes('dangerously') && !this.hasSanitization(content)) {
        findings.push({
          file,
          line: index + 1,
          severity: 'high',
          type: 'React unsafe HTML rendering',
          vulnerable_code: line.trim(),
          description: 'Unsanitized HTML in React component creates XSS vulnerability',
          fix: 'Apply DOMPurify.sanitize() before rendering or use safe alternatives',
          cwe: 'CWE-79'
        });
      }
    });

    return findings;
  }

  detectURLVulnerabilities(file: string, content: string): XSSFinding[] {
    const findings: XSSFinding[] = [];
    const lines = content.split('\n');

    lines.forEach((line, index) => {
      if (line.includes('location.') && this.hasUserInput(line)) {
        findings.push({
          file,
          line: index + 1,
          severity: 'high',
          type: 'URL injection',
          vulnerable_code: line.trim(),
          description: 'User input in URL assignment can execute malicious code',
          fix: 'Validate URLs and enforce http/https protocols only',
          cwe: 'CWE-79'
        });
      }
    });

    return findings;
  }

  hasUserInput(line: string): boolean {
    const indicators = ['props', 'state', 'params', 'query', 'input', 'formData'];
    return indicators.some(indicator => line.includes(indicator));
  }

  hasSanitization(content: string): boolean {
    return content.includes('DOMPurify') || content.includes('sanitize');
  }
}

2. Framework-Specific Detection

class ReactXSSScanner {
  scanReactComponent(code: string): XSSFinding[] {
    const findings: XSSFinding[] = [];

    // Check for unsafe React patterns
    const unsafePatterns = [
      'dangerouslySetInnerHTML',
      'createMarkup',
      'rawHtml'
    ];

    unsafePatterns.forEach(pattern => {
      if (code.includes(pattern) && !code.includes('DOMPurify')) {
        findings.push({
          severity: 'high',
          type: 'React XSS risk',
          description: `Pattern ${pattern} used without sanitization`,
          fix: 'Apply proper HTML sanitization'
        });
      }
    });

    return findings;
  }
}

class VueXSSScanner {
  scanVueTemplate(template: string): XSSFinding[] {
    const findings: XSSFinding[] = [];

    if (template.includes('v-html')) {
      findings.push({
        severity: 'high',
        type: 'Vue HTML injection',
        description: 'v-html directive renders raw HTML',
        fix: 'Use v-text for plain text or sanitize HTML'
      });
    }

    return findings;
  }
}

3. Secure Coding Examples

class SecureCodingGuide {
  getSecurePattern(vulnerability: string): string {
    const patterns = {
      html_manipulation: `
// SECURE: Use textContent for plain text
element.textContent = userInput;

// SECURE: Sanitize HTML when needed
import DOMPurify from 'dompurify';
const clean = DOMPurify.sanitize(userInput);
element.innerHTML = clean;`,

      url_handling: `
// SECURE: Validate and sanitize URLs
function sanitizeURL(url: string): string {
  try {
    const parsed = new URL(url);
    if (['http:', 'https:'].includes(parsed.protocol)) {
      return parsed.href;
    }
  } catch {}
  return '#';
}`,

      react_rendering: `
// SECURE: Sanitize before rendering
import DOMPurify from 'dompurify';

const Component = ({ html }) => (
  <div dangerouslySetInnerHTML={{
    __html: DOMPurify.sanitize(html)
  }} />
);`
    };

    return patterns[vulnerability] || 'No secure pattern available';
  }
}

4. Automated Scanning Integration

# ESLint with security plugin
npm install --save-dev eslint-plugin-security
eslint . --plugin security

# Semgrep for XSS patterns
semgrep --config=p/xss --json

# Custom XSS scanner
node xss-scanner.js --path=src --format=json

5. Report Generation

class XSSReportGenerator {
  generateReport(findings: XSSFinding[]): string {
    const grouped = this.groupBySeverity(findings);

    let report = '# XSS Vulnerability Scan Report\n\n';
    report += `Total Findings: ${findings.length}\n\n`;

    for (const [severity, issues] of Object.entries(grouped)) {
      report += `## ${severity.toUpperCase()} (${issues.length})\n\n`;

      for (const issue of issues) {
        report += `- **${issue.type}**\n`;
        report += `  File: ${issue.file}:${issue.line}\n`;
        report += `  Fix: ${issue.fix}\n\n`;
      }
    }

    return report;
  }

  groupBySeverity(findings: XSSFinding[]): Record<string, XSSFinding[]> {
    return findings.reduce((acc, finding) => {
      if (!acc[finding.severity]) acc[finding.severity] = [];
      acc[finding.severity].push(finding);
      return acc;
    }, {} as Record<string, XSSFinding[]>);
  }
}

6. Prevention Checklist

HTML Manipulation

• Never use innerHTML with user input
• Prefer textContent for text content
• Sanitize with DOMPurify before rendering HTML
• Avoid document.write entirely

URL Handling

• Validate all URLs before assignment
• Block javascript: and data: protocols
• Use URL constructor for validation
• Sanitize href attributes

Event Handlers

• Use addEventListener instead of inline handlers
• Sanitize all event handler input
• Avoid string-to-code patterns

Framework-Specific

• React: Sanitize before using unsafe APIs
• Vue: Prefer v-text over v-html
• Angular: Use built-in sanitization
• Avoid bypassing framework security features

Imported: Context

The user needs comprehensive XSS vulnerability scanning for client-side code, identifying dangerous patterns like unsafe HTML manipulation, URL handling issues, and improper user input rendering. Focus on context-aware detection and framework-specific security patterns.

Examples

Example 1: Ask for the upstream workflow directly

Use @frontend-mobile-security-xss-scan to handle <task>. Start from the copied upstream workflow, load only the files that change the outcome, and keep provenance visible in the answer.

Explanation: This is the safest starting point when the operator needs the imported workflow, but not the entire repository.

Example 2: Ask for a provenance-grounded review

Review @frontend-mobile-security-xss-scan against metadata.json and ORIGIN.md, then explain which copied upstream files you would load first and why.

Explanation: Use this before review or troubleshooting when you need a precise, auditable explanation of origin and file selection.

Example 3: Narrow the copied support files before execution

Use @frontend-mobile-security-xss-scan for <task>. Load only the copied references, examples, or scripts that change the outcome, and name the files explicitly before proceeding.

Explanation: This keeps the skill aligned with progressive disclosure instead of loading the whole copied package by default.

Example 4: Build a reviewer packet

Review @frontend-mobile-security-xss-scan using the copied upstream files plus provenance, then summarize any gaps before merge.

Explanation: This is useful when the PR is waiting for human review and you want a repeatable audit packet.

Best Practices

Treat the generated public skill as a reviewable packaging layer around the upstream repository. The goal is to keep provenance explicit and load only the copied source material that materially improves execution.

• Keep the imported skill grounded in the upstream repository; do not invent steps that the source material cannot support.
• Prefer the smallest useful set of support files so the workflow stays auditable and fast to review.
• Keep provenance, source commit, and imported file paths visible in notes and PR descriptions.
• Point directly at the copied upstream files that justify the workflow instead of relying on generic review boilerplate.
• Treat generated examples as scaffolding; adapt them to the concrete task before execution.
• Route to a stronger native skill when architecture, debugging, design, or security concerns become dominant.

Troubleshooting

Problem: The operator skipped the imported context and answered too generically

Symptoms: The result ignores the upstream workflow in

plugins/antigravity-awesome-skills-claude/skills/frontend-mobile-security-xss-scan

metadata.json

ORIGIN.md

Problem: The imported workflow feels incomplete during review

Symptoms: Reviewers can see the generated

SKILL.md

Problem: The task drifted into a different specialization

Symptoms: The imported skill starts in the right place, but the work turns into debugging, architecture, design, security, or release orchestration that a native skill handles better. Solution: Use the related skills section to hand off deliberately. Keep the imported provenance visible so the next skill inherits the right context instead of starting blind.

Related Skills

• @2d-games

  - Use when the work is better handled by that native specialization after this imported skill establishes context.

• @3d-games

  - Use when the work is better handled by that native specialization after this imported skill establishes context.

• @daily-gift

  - Use when the work is better handled by that native specialization after this imported skill establishes context.

• @design-taste-frontend

  - Use when the work is better handled by that native specialization after this imported skill establishes context.

Additional Resources

Use this support matrix and the linked files below as the operator packet for this imported skill. They should reflect real copied source material, not generic scaffolding.

references

references/n/a

examples

examples/n/a

scripts

scripts/n/a

agents

agents/n/a

assets

assets/n/a

Imported Reference Notes

Imported: Requirements

$ARGUMENTS

Imported: Output Format

1. Vulnerability Report: Detailed findings with severity levels
2. Risk Analysis: Impact assessment for each vulnerability
3. Fix Recommendations: Secure code examples
4. Sanitization Guide: DOMPurify usage patterns
5. Prevention Checklist: Best practices for XSS prevention

Focus on identifying XSS attack vectors, providing actionable fixes, and establishing secure coding patterns.

Imported: Limitations

• Use this skill only when the task clearly matches the scope described above.
• Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
• Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.