Critical · published December 12, 2024
🚨 A residual gap in http4k could allow attackers to exploit XML documents and unleash chaos on your server! 🔥 Think of it like a restaurant that blocks outside food but still lets patrons bring in takeout containers filled with mystery meals — the kitchen can't control what sneaks in! An attacker could unleash a billion-laughs attack, causing a denial of service by overwhelming your application with resource-hogging requests. Worse yet, they could read sensitive local files or even execute commands on your server, turning a simple XML request into a devastating breach. Yikes!
Think of it like a restaurant that blocks outside food but still lets patrons bring in takeout containers filled with mystery meals — the kitchen can't control what sneaks in! This XXE vulnerability stems from the parser accepting documents with `<!DOCTYPE>` declarations, which, despite blocking external entities, can still be exploited for internal entity expansion attacks. Versions prior to 6.50.0.0 are impacted, but the latest release fixes this by rejecting such declarations outright.
An attacker could unleash a billion-laughs attack, causing a denial of service by overwhelming your application with resource-hogging requests. Worse yet, they could read sensitive local files or even execute commands on your server, turning a simple XML request into a devastating breach. Yikes! Update http4k to version 6.50.0.0 or later immediately to close this critical vulnerability. Ensure that your XML handling is configured to disallow doctype declarations and enable secure processing features. Don't forget to audit your applications that handle untrusted XML! You're a security hero in the making! Follow these steps and keep your server safe from sneaky XML attacks! 🛡️