Episode 169: Attacking OAuth 2.1

Episode 169: In this episode of Critical Thinking - Bug Bounty Podcast gr3pme goes over some of the changes from OAuth 2.0 vs 2.1 and how Hackers can capitalize.

Follow us on twitter at: https://x.com/ctbbpodcast

Got any ideas and suggestions? Feel free to send us any feedback here: info@criticalthinkingpodcast.io

Shoutout to YTCracker for the awesome intro music!

====== Links ======

Follow your hosts Rhynorater, rez0 and gr3pme on X: 

https://x.com/Rhynorater

https://x.com/rez0__

https://x.com/gr3pme

Critical Research Lab:

https://lab.ctbb.show/ 

====== Ways to Support CTBBPodcast ======

Hop on the CTBB Discord at https://ctbb.show/discord!

We also do Discord subs at $25, $10, and $5 - premium subscribers get access to private masterclasses, exploits, tools, scripts, un-redacted bug reports, etc.

You can also find some hacker swag at https://ctbb.show/merch!

Today's Sponsor: Check out ThreatLocker Ringfencing

https://www.criticalthinkingpodcast.io/tl-rf

====== This Week in Bug Bounty ======

Intigriti is providing free Burp Pro for Hackers!

https://www.intigriti.com/blog/news/intigriti-collaborates-with-portswigger-to-support-ethical-hacking-excellence

====== Resources ======

Django-allauth Account Takeover (ZeroPath Audit)

https://zeropath.com/blog/django-allauth-account-takeover-vulnerabilities

CVE-2025-4144: Cloudflare Workers PKCE Bypass

https://github.com/cloudflare/workers-oauth-provider/security/advisories/GHSA-qgp8-v765-qxx9

CVE-2025-54576: OAuth2-Proxy Auth Bypass

https://zeropath.com/blog/cve-2025-54576-oauth2-proxy-auth-bypass

====== Timestamps ======

(00:00:00) Introduction

(00:02:16) OAuth 2.0 Standards

(00:12:08) Agent to Agent Communication

(00:17:19) CVE Case studies