OAuth vulnerabilities have been a recurring issue, affecting even sophisticated platforms due to complex implementation challenges and subtle weaknesses. The text explores several notable cases, including token theft from GitHub, Heroku, and Travis CI, redirect manipulation at Booking.com, a proxy vulnerability at Expo, a domain takeover exploit involving Google OAuth, and a misconfiguration in Microsoft Azure Active Directory. Each incident highlights different flaws, such as poor token storage, inadequate redirect validation, reliance on mutable email claims, and insufficient domain verification. The incidents underscore the importance of robust security measures, like regular audits, strict parameter validation, and the use of immutable identifiers, to mitigate OAuth risks. Despite patches and ongoing investigations, these cases demonstrate the persistent challenges in OAuth security, emphasizing the need for expertise and possibly outsourcing to managed authentication services to maintain security integrity.