01
Teams of one to four
Solo entries are welcome. Teams may have up to four registered members. Rosters lock one hour before kickoff and cannot be edited mid-event.
// Rulebook
Read these
before kickoff.
Our rules are short, practical and enforced. We default to trust whenever possible. We also remove rule-breakers from the leaderboard without negotiation.
02
No flag sharing
Sharing flags or full solutions outside your team — even after solving — is grounds for immediate disqualification. Public writeups are encouraged once the event has ended.
03
No infrastructure attacks
No platform DoS, no flag-submission brute force, no sandbox escape into our infrastructure. Stay inside the boundaries of each individual challenge.
04
AI assistance is allowed
You may use language models, code assistants and any other tooling. Challenges are designed to resist naive prompt-and-paste workflows: the reasoning still has to come from you.
05
Report unintended solves
Found a shortcut the authors did not intend? Tell us during the event. We will fix the challenge if needed and credit you in the post-event writeup.
06
Be kind, on principle
The competition exists because we genuinely enjoy the craft. We expect every participant to extend that same energy to the rest of the community.
ZeroArenaCTF welcomes participants of every skill level and background. Harassment, slurs, doxxing and bad-faith behaviour in any of our community spaces will result in removal without notice. — Code of conduct, abridged
Discord moderators have final discretion, and concerns can be flagged privately by direct-messaging any moderator. If something feels off during the event, ping us in the dedicated channel — we would much rather hear about it early than learn about it during the post-mortem.
Things participants
tend to ask.
Is the event free to play?
Yes. Sponsors cover the prize pool and the cost of running the platform infrastructure.
Do I need a team?
No. Solo participation is supported and ranked on the same leaderboard as teams.
What level is the CTF aimed at?
A mix. Easy challenges welcome newcomers; Insane-tier challenges are designed to occupy a full team for an entire night. Categories are balanced so you can stay primarily in your favourite track.
Will writeups be published after the event?
Yes. Authors publish official writeups within seven days of the event ending. Community writeups are featured on the site as they become available.
Can I use AI assistants and language models?
Yes — but they alone will not be enough. Our hardest challenges intentionally require human reasoning at one or more stages, and the easy ones are still multi-stage on purpose.
How is the scoring done?
Dynamic scoring: each challenge starts at its maximum value and decays as more teams solve it, down to a documented floor. Ties are broken strictly by first-solve timestamp.
Which time zone does the event use?
CEST (Central European Summer Time, UTC+2). Kickoff is at 20:00 on Friday, 29 May 2026.
How do I get hints during the event?
Each challenge ships with optional hints unlocked from the platform at a fixed point cost. Direct messages to authors during the event are not accepted.
What happens after submission closes?
Submissions stop at 23:59 CEST on Saturday. Final scoring is published shortly after, followed by the awards stream and the writeup release schedule.
I found a bug in the platform — what do I do?
Drop a message in the dedicated #infra-issues channel on Discord. We monitor it continuously during the event and within working hours otherwise.
Still unsure
Ask us directly.
The Discord server is the fastest way to get a clarification, and the conversation is usually useful for other participants too.