On 21 October 2026, Google released patched versions of its Brotli compression library for CVE-2026-111497, a vulnerability nicknamed Node2Shell. It is an out-of-bounds write in the Brotli decoder. Node and many Python stacks bundle their own copy of Brotli, so patching libbrotli on the host doesn't fix them.

I made an interactive, hands-on lab exercise on this vulnerability. The goal is to give engineers a general overview of the attack vector and the response. You'll exploit a service as an attacker, then switch roles to the on-call engineer: upgrade the runtimes, rebuild and redeploy the images, verify the fix, and rotate the deploy token the attacker read from memory.

I did my best to highlight all the details, but if you notice any issues or inconsistencies, please let me know!

https://ransomleak.com/exercises/http2shell-rce/