Type to search across the blog, guides, tools, and services.
↑↓
to navigate
↵
to open
Vulnerability
Hackers steal millions of user records from Gyazo
Help Net Security covered this vulnerability on Sep 21, 2026. Below is a plain-English breakdown of what it is, how it actually works, and whether it matters, written for people who are curious about hacking and security but don't have a technical background.
Help Net Security · Sep 21, 2026
In plain words
Imagine you have a box where you store your personal stuff, and someone finds a way to unlock the box and take everything inside. That's kind of what happened here, but instead of a physical box, it's a server that stores user data. A server is like a big computer that holds lots of information.
What's broken
The bug is in Gyazo's image upload server, which is a part of their system that handles users' screenshots and screen recordings. The company says an attacker exploited this vulnerability¹ to steal approximately 23.62 million user records and metadata tied to hundreds of millions of images. A vulnerability¹ is like a weak point in a system that can be used to gain unauthorized access.
How it actually works
Here's how it works: when you upload a screenshot to Gyazo, it goes to their server. If there's a flaw in the server's security, like this vulnerability¹, an attacker can use it to get into the system and take data. The attacker can then use this access to move around the system and find more data to steal. It's like finding an unlocked door and then being able to walk around the house and take whatever you want.
Terms
¹ vulnerability
, A weakness in a system that can be used to gain unauthorized access
Learn the fundamentals
Want to understand the concepts behind this item? These in-depth HackproofHacks guides explain the
underlying techniques from the ground up.
KeepLooped tracks the newest
offensive-security tools, techniques, vulnerabilities and research from 80+ trusted sources and turns the
most important items into plain-language explainers, so people learning security can keep up without a
technical background. This page summarises and explains the source linked below; it was produced with AI
assistance and is meant as a beginner-friendly starting point. Always confirm specifics, versions, CVE
details, and exploitation status, against the original source and official advisories. Curated and
published by HackproofHacks.