squ1rrel CTF 2026
13 challenges with 37 published solutions between them. No writeups were ever filed against this event's listing, so its solutions were found in public repositories instead. Each link is pinned to the commit it was read from.
The event listingWeb5
Reach data or functionality the application meant to keep from you - through its inputs, its tokens, or its trust in the client.
Mongolia
4 official solutionsAlso written up in: c0dn/squ1rrel-ctf-2026-writeups, hax1ng/squ1rrel-CTF-2026-Writeups, c0dn/squ1rrel-ctf-2026-writeups, hax1ng/squ1rrel-CTF-2026-Writeups
Mongolia 2
4 official solutionsAlso written up in: c0dn/squ1rrel-ctf-2026-writeups, hax1ng/squ1rrel-CTF-2026-Writeups, c0dn/squ1rrel-ctf-2026-writeups, hax1ng/squ1rrel-CTF-2026-Writeups
Artifacts
3 official solutionsAlso written up in: c0dn/squ1rrel-ctf-2026-writeups, c0dn/squ1rrel-ctf-2026-writeups, c0dn/squ1rrel-ctf-2026-writeups
Model Behavior
2 official solutionsAlso written up in: hax1ng/squ1rrel-CTF-2026-Writeups, hax1ng/squ1rrel-CTF-2026-Writeups
Subtick
2 official solutionsAlso written up in: c0dn/squ1rrel-ctf-2026-writeups, c0dn/squ1rrel-ctf-2026-writeups
Misc3
Everything that fits no other box: esolangs, puzzles, scripting exercises, and the jail escapes that have not yet earned their own category.
Soulmate
4 official solutionsAlso written up in: c0dn/squ1rrel-ctf-2026-writeups, hax1ng/squ1rrel-CTF-2026-Writeups, c0dn/squ1rrel-ctf-2026-writeups, hax1ng/squ1rrel-CTF-2026-Writeups
Pdfpile
3 official solutionsAlso written up in: c0dn/squ1rrel-ctf-2026-writeups, hax1ng/squ1rrel-CTF-2026-Writeups, c0dn/squ1rrel-ctf-2026-writeups
Bawk Bawk
2 official solutionsAlso written up in: hax1ng/squ1rrel-CTF-2026-Writeups, hax1ng/squ1rrel-CTF-2026-Writeups
Reverse engineering3
Work out what a compiled program does without its source, then work backwards from the check to the input that passes it.
Squ1rrel O Tron
4 official solutionsAlso written up in: c0dn/squ1rrel-ctf-2026-writeups, hax1ng/squ1rrel-CTF-2026-Writeups, c0dn/squ1rrel-ctf-2026-writeups, hax1ng/squ1rrel-CTF-2026-Writeups
Squ1rrel O Tron 2
4 official solutionsAlso written up in: c0dn/squ1rrel-ctf-2026-writeups, hax1ng/squ1rrel-CTF-2026-Writeups, c0dn/squ1rrel-ctf-2026-writeups, hax1ng/squ1rrel-CTF-2026-Writeups
Redactr
2 official solutionsAlso written up in: hax1ng/squ1rrel-CTF-2026-Writeups, hax1ng/squ1rrel-CTF-2026-Writeups
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.
Also written up in: hax1ng/squ1rrel-CTF-2026-Writeups, hax1ng/squ1rrel-CTF-2026-Writeups
Uncategorised1
The upstream scoreboard did not say, so neither do we.
Squ1rrelmail
1 official solutionAlso written up in: jeff-160/CTF-writeups