Cybersecurity hackathons and CTFs (2026)
Cybersecurity hackathons ask teams to build security tools or defend systems, while capture-the-flag (CTF) competitions are puzzles where you find hidden flags by exploiting deliberately vulnerable challenges in web, crypto, forensics and reverse engineering.
Each listing shows the format (build or CTF), the categories and the prizes.
Open and upcoming
Nothing is open here right now. New hackathons are added every week.
Frequently asked questions
What is a CTF competition?
Capture the flag is a security contest: each challenge hides a text “flag” you can only reach by solving a security problem. Teams score points for every flag they submit.
Do I have to pay to register on Hack4Hack?
No. A Hack4Hack account is free, and most hackathons are free to enter. When an organizer charges a fee, it is shown on the hackathon page before you register.