The original title is: "Reject Image Polyglots After EXIF Removal, Before They Reach Your CDN"

Short summary

EXIF removal alone doesn't guarantee an uploaded JPEG is only a JPEG—attackers can append ZIP or HTML payloads after the image end marker. The author recommends a multi-layer upload gate: quarantine originals, enforce size and dimension limits, decode and re-encode pixels into a fresh file, then publish only the derived output. Re-encoding is stronger than boundary checks because it creates a new representation from decoded pixels, discarding all trailing bytes and metadata.

• •EXIF stripping does not prevent polyglot image attacks
• •Re-encode uploaded images to discard trailing payloads and metadata
• •Publish only server-generated derived files; keep originals quarantined

Generated with AI, which can make mistakes.