High · published January 8, 2026
⚡ A crafty username can crash your CTF party! The user profile API in Flag Forge versions 2.3.2 and below has a sneaky Regular Expression Denial of Service (ReDoS) vulnerability just waiting to be exploited. 🚨 Think of this vulnerability like a restaurant that gets so many complicated orders that the kitchen gets backed up — one tricky dish can hold up the whole service. If an attacker specifies a username with regex meta-characters, it’s like sending an overly elaborate order that the cooks just can’t handle! If an attacker sends a specially crafted username, they could cause the MongoDB regex engine to go haywire, consuming all the CPU resources. This could lead to a Denial of Service for other users, effectively shutting down your CTF platform when they need it most!
Think of this vulnerability like a restaurant that gets so many complicated orders that the kitchen gets backed up — one tricky dish can hold up the whole service. If an attacker specifies a username with regex meta-characters, it’s like sending an overly elaborate order that the cooks just can’t handle! This ReDoS vulnerability arises because the application dynamically builds a regular expression using unsanitized user input (the username). When maliciously crafted input is received, it results in excessive CPU consumption, rendering the service unavailable.
If an attacker sends a specially crafted username, they could cause the MongoDB regex engine to go haywire, consuming all the CPU resources. This could lead to a Denial of Service for other users, effectively shutting down your CTF platform when they need it most! To combat this, upgrade your Flag Forge to version 2.3.3 immediately! Additionally, implement a Web Application Firewall (WAF) rule that blocks requests containing regex meta-characters in the URL path to prevent future exploits. You've got this! With these steps, you’ll have your Flag Forge platform running smoothly in no time! 🛡️