Sjoerd Langkemper

PHP has several superglobal variables which contain values from the request or the environment.

At our scouting clubhouse we have lights in the toilet that turn on automatically when you enter.

Zdir is a webapp that lists files in a directory, with preview and download functionality.

Here are some links I thought were interesting from the past year.

Computers can only store bits and bytes.

CVE-2025-25200 describes a regex denial of service (ReDoS) in the Koa web framework.

Open Web Analytics (OWA) is a web app that tracks website visitors.

Previously, I wrote about encrypting identifiers.

Here are some links to interesting cybersecurity articles from 2024.

An image on your site can be directly included in other sites.