2026weight 85.48UMDCSEC

UMDCTF 2026

3 challenges with 3 published community solutions between them. Solution links go to CTFtime’s task page, which aggregates every writeup for a challenge - individual blog posts rot, the aggregator does not.

Full task list on CTFtime

Cryptography1

Recover a plaintext or a key from something that was supposed to protect it. In practice: identify the scheme, find the parameter the author got wrong, exploit it.

Solve it with:Cipher identifier and automatic decoder Vigenere cipher solver with automatic key recovery RSA decryption and attack runner Wiener’s attack on small RSA private exponents In-browser hash cracker with rule transforms Learn: Classical ciphers and frequency analysis Learn: RSA and the parameters that break it

quant?
72 pts1 writeup
- quantum
Same technique in picoCTF: StegoRSA, Timestamped Secrets, AES-ABC

Binary exploitation1

Turn a memory-safety bug in a native binary into control of execution. Usually a stack overflow, a format string, or a heap primitive.

Solve it with:ROP gadget finder Shellcode assembler and library Cyclic pattern generator and offset finder Format string exploit builder Learn: Binary exploitation

bookmaker
211 pts1 writeup
- pwn
Same technique in picoCTF: Guessing Game 1, x-sixty-what, format string 3

Reverse engineering1

Work out what a compiled program does without its source, then work backwards from the check to the input that passes it.

Solve it with:Strings extractor for binaries and blobs WebAssembly disassembler Java .class disassembler Python .pyc bytecode disassembler Learn: Binary exploitation

nuclear_codes
106 pts1 writeup
- reverse
- engineering
Same technique in picoCTF: WinAntiDbg0x100, WinAntiDbg0x200, WinAntiDbg0x300

Cryptography1

quant?

Binary exploitation1

bookmaker

Reverse engineering1

nuclear_codes

Other 2026 events