XSS in pastebin.com and reddit.com via unsanitized Markdown Output

The pastebin case

The second PoC




  • 22/12/17 Vulnerability found
  • 23/12/17 Vulnerability reported
  • 24/12/17 First contact with the administrators, they were kind enough to provide me with a premium lifetime account and the promise to patch ASAP
  • 02/04/18 I sent a mail to the administrators to solicit the patch and ask information about the disclosure details
  • 10/04/18 I received a mail saying that the vulnerability was patched
  • 10/04/18 I sent a reply containing a new PoC with a bypass for the current patch
  • 11/04/18 Patch for the second PoC released
  • 13/04/18 Vulnerability found on reddit.com
  • 13/04/18 Vulnerability reported to reddit team
  • 13/04/18 First hotfix released
  • 23/04/18 Final path deployed

Interested in my works?




Developer and Security Researcher

Love podcasts or audiobooks? Learn on the go with our new app.

Recommended from Medium

{UPDATE} Big Construction Bulldozer Driving 3D - Heavy Vehicle Driver Simulator Game Hack Free…

CMGT 245 Entire Course CMGT/245// https://uopcourses.com  IS SECURITY CONCEPTS


Cyber Security Headlines for the Week

{UPDATE} Super Hotel Tycoon Hack Free Resources Generator

Clean Reinstall Spotify Mac

NFTP IDO is Live on Dxsale

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
Francesco Giordano

Francesco Giordano

Developer and Security Researcher

More from Medium

An Introduction to Cross-Site Request Forgery

Testing WebSockets for Vulnerabilities {Part-1} The Basics.

Everything About Path Traversal Vulnerability

eLearnSecurity Web Application Penetration Tester Review