Daily AlpacaHack

A daily CTF challenge with a fun new puzzle every day

What is Daily AlpacaHack?

We publish one simple, beginner-friendly or educational CTF challenge every day!

Join Anytime

Solve within 24 hours of release to appear on the leaderboard.

Not a Competition

Discussion with friends or AI is welcome (account sharing is prohibited).

Solution Sharing Rules

Sharing solutions is allowed only after 24 hours have passed since release.

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Today's Challenge

Submissions (latest 3)

ctf-udon

SOLVED!

May 10, 4:43 PM

nanashiku

SOLVED!

May 10, 4:42 PM

tsuji1

SOLVED!

May 10, 4:30 PM

Leaderboard

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Try the first challenge

Is this your first CTF? Let's begin by tackling the first challenge released on Daily AlpacaHack.

Upcoming challenges reveal the , , and in advance.

May 2026

Solved

Unsolved

Upcoming

Mon

Tue

Wed

Thu

Fri

Sat

Sun

shiragi

Unrevealed TXT

Misc

Easy🌱

123 solves

serioton

unheard

Misc

Medium

74 solves

minaminao

permission denied

Misc

Hard

76 solves

minaminao

permission denied 2

Misc

Medium

76 solves

admin

Alpaca++

Misc

Welcome🌱

186 solves

tchen

Alpaca Rangers 2

Web

Easy🌱

161 solves

pppp4649

Small N

Crypto

Easy🌱

125 solves

hiikunz

secret-table-2

Web

Medium

120 solves

serioton

do the math

Misc

Medium

103 solves

trimscash

func-array

Pwn

Easy🌱

116 solves

minaminao

permission denied 3

Misc

Medium

104 solves

baumroll1234

Vending Machine

Misc

Easy🌱

146 solves

hiikunz

reused n

Crypto

Medium

99 solves

rsk0315

Bounds Checking

Pwn

Hard

67 solves

serioton

Mirage

Rev

Easy🌱

27 solves

minaminao

Planned topicDocker

Misc

Medium

Coming soon

k0080

Planned topicProcedure Linkage Table

Pwn

Hard

Coming soon

k0080

Planned topicCUDA

Rev

Hard

Coming soon

ptr-yudai

Planned topicStack

Pwn

Hard

Want a harder challenge?

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Writeups

Writeup for Bounds Checking baumroll1234 ja Bounds Checking 1 hour ago
Writeup for Bounds Checking tadanobutubutu ja Bounds Checking 1 hour ago
Writeup for Bounds Checking goroshirow ja Bounds Checking 1 hour ago
Writeup for reused n y8w3ly en reused n 2 hours ago
AlpacaHackで始めるCTF入門8：初めてのDaily AlpacaHackに挑戦 yusukekato ja Vending Machine 9 hours ago
Writeup for reused n tadanobutubutu ja reused n 23 hours ago
Writeup for reused n baumroll1234 ja reused n yesterday
Writeup for Daily AlpacaHack 5/3-5/9 kakur41 ja reused n +6 yesterday
Writeup for reused n goroshirow ja reused n yesterday
Writeup for Vending Machine baumroll1234 author ja Vending Machine yesterday

Rows:

Mirage

Topic: LFSRReleased: May 11, 2026

27 solves

Rev

Easy🌱

serioton

Not everything you see is what it seems.

mirage.tar.gz

description solves