SVG Security: Protecting Your Website from Vector Attacks

Why SVG Security Matters

SVGs are more than simple images—they can contain JavaScript, external references, and other potentially dangerous content. Understanding these risks is essential for any developer working with user-uploaded or external SVGs.

SVG Attack Vectors

Embedded JavaScript

SVGs can run code:

Event Handlers

JavaScript via attributes:

External Resources

Loading external content:

XML Attacks

XXE and Billion Laughs:

  
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Risk Assessment

When SVGs Are Dangerous

High-risk scenarios:

When SVGs Are Safe

Lower-risk scenarios:

Mitigation Strategies

Content Security Policy

Strong CSP headers:

Content-Security-Policy:
  default-src 'self';
  script-src 'self';
  style-src 'self' 'unsafe-inline';
  img-src 'self' data:;
  object-src 'none';

Display as Image

Disable script execution:

SVG Sanitization

Remove dangerous content:

// Using DOMPurify
import DOMPurify from 'dompurify';
const sanitizedSVG = DOMPurify.sanitize(untrustedSVG, {
  USE_PROFILES: { svg: true },
  ADD_TAGS: ['use'],
  FORBID_TAGS: ['script'],
  FORBID_ATTR: ['onclick', 'onload', 'onerror']
});

Server-Side Validation

Check uploads before storage:

function validateSVG(svgContent) {
  const dangerous = [
    /

Vectosolve Security

Clean Output

Vectosolve produces safe SVGs:

Safe for Use

Vectosolve-generated SVGs:

Security Checklist

For Developers

✓ Never trust user-uploaded SVGs ✓ Always sanitize before display ✓ Use CSP headers ✓ Display as images when possible ✓ Validate on server side ✓ Monitor for abuse

For Designers

✓ Use trusted tools only ✓ Review SVG source ✓ Remove unnecessary elements ✓ Use reputable vectorization services

Conclusion

SVG security requires understanding the format's capabilities and implementing appropriate safeguards. When handling untrusted SVGs, always sanitize, validate, and display safely. Using Vectosolve for conversions ensures clean, safe output free from security concerns.

Get Clean, Safe SVGs