CDCTF 2026
- Starts
- Ends
- Runs for
- 12 hours
- Format
- Jeopardy (online)
- Rating weight
- 25.00 - Strong field
- Teams registered
- 5
Run by Crimson Defense, with prizes listed on CTFtime.
What the organisers say
Crimson Defense CTF 2026 will be held on Saturday, October 3rd from 10am to 10pm CDT! CDCTF is a virtual 12-hour Jeopardy-style Capture-the-Flag competition designed for collegiate-level players. All ability levels are welcome. This competition will not only provide satisfying challenges for seasoned players, but be a good introduction to CTFs for new ones!
Prep briefing
What past editions were made of
Counted across 10 challenges from 2026, 2025, using the categories the scoreboards themselves used. Two things to hold in mind while reading it. The archive indexes challenges that someone published a solution to, not whole scoreboards, so this is the shape of what people wrote about rather than of everything that was set. And where a scoreboard gave no category the challenge lands in misc, so a large misc slice means “unlabelled” rather than “miscellaneous”.
10 challenges is a thin sample. Read the split below as a hint about this event rather than as its profile, and lean on the linked editions instead - they are the actual record.
- forensics 50%(2)
- web 25%(1)
- pwn 25%(1)
What to have open when it starts
Forensics
Start with the file's own claim about itself, then with what is appended after it ends. Both are one paste away.
- File type identifier by magic bytes
- Hex viewer and hexdump
- ZIP archive inspector
- PCAP analyzer for CTF network forensics
- Memory dump, disk image and registry hive analysis
New to this? Read File forensics and carving, Network forensics, Memory and disk forensics
Web
Read the token before you read the source. A session cookie that decodes is the shortest path through half the web board.
- JWT decoder and signature verifier
- Flask session cookie decoder
- HTTP request replayer
- Directory and path scanner
- HTTP security header analyzer
New to this? Read Web attacks and session tokens
Pwn
Get the offset and the libc base mechanically, so the thinking is spent on the chain rather than on arithmetic.
- Cyclic pattern generator and offset finder
- Buffer overflow offset finder
- Libc base address calculator
- ROP gadget finder
- Pwntools exploit script generator
New to this? Read Binary exploitation
The challenges people wrote about most
From previous editions, ordered by how many published solutions each attracted. Reading two solutions to one of these is the closest thing to a warm-up for this event that exists.
- Accountpwn · 2025 · 1 writeup
- Challenge Templateunknown · 2026 · 1 writeup
- Collectorweb · 2025 · 1 writeup
- Eventunknown · 2026 · 1 writeup
- FindTheRendevousforensics · 2025 · 1 writeup
- Kraken AESunknown · 2026 · 1 writeup