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.
The replace_first filter in LiquidJS uses JavaScript's String.prototype.replace() which interprets $& as a backreference to the matched substring. The filter only charges memoryLimit for the input string length, not the amplified output. An attacker can achieve exponential memory amplification (up to 625,000:1) while staying within the memoryLimit budget, leading to denial of service.
The layout, render, and include tags allow arbitrary file access via absolute paths (either as string literals or through Liquid variables, the latter require dynamicPartials: true, which is the default). This poses a security risk when malicious users are allowed to control the template content or specify the filepath to be included as a Liquid variable.
The package liquidjs before 10.0.0 is vulnerable to Information Exposure when ownPropertyOnly parameter is set to False, which results in leaking properties of a prototype. Workaround For versions 9.34.0 and higher, an option to disable this functionality is provided.