LiquidJS is a Shopify / GitHub Pages compatible template engine in pure JavaScript. Prior to version 10.25.1, LiquidJS's "memoryLimit" security mechanism can be completely bypassed by using reverse range expressions (e.g., "(100000000..1)"), allowing an attacker to allocate unlimited memory. Combined with a string flattening operation (e.g., "replace" filter), this causes a V8 Fatal error that crashes the Node.js process, resulting in complete denial of service from a single HTTP request. Version 10.25.1 patches the issue.