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We are aware of the recently disclosed PHP2Shell vulnerabilities (CVE-2026-109618 and CVE-2026-109619) and can confirm Filestack is not impacted by these vulnerabilities.

Filestack Technical Glossary

Comprehensive reference for Filestack platform architecture and services

User Agent Detection

Optimization

Browser identification method used to optimize Filestack’s services for different browsers and devices.

Optimization Targets

  • Browser-specific feature support
  • Device capability detection
  • Format compatibility optimization
  • Performance optimization per platform

Use Cases

  • Optimal image format selection (WebP, AVIF)
  • Feature detection for File Picker
  • Mobile-specific optimizations
  • Browser compatibility handling

Implementation

Automatically applied by Filestack services to provide optimal experience across all supported platforms.

Related Terms