Description
LiquidJS is a Shopify/GitHub Pages compatible template engine written in pure JavaScript. In versions 10.25.7 and below, the renderLimit option can be fully bypassed by a {% for %} (or {% tablerow %}) tag whose body is empty. The renderLimit option is documented in docs/source/tutorials/dos.md as the mechanism that "mitigates this by limiting the time consumed by each render() call." The per-iteration time check is reached only when the body contains at least one template node, so a template such as {%- for i in (1..N) -%}{%- endfor -%} iterates the full collection without ever consulting renderLimit. With a configured renderLimit of 50 ms, a single parseAndRenderSync call has been observed to consume 2.26 seconds (~45× over the limit) and scales linearly with N up to memoryLimit, allowing a low-privileged template author to wedge an event-loop thread for an attacker-chosen duration. Deployments that rely on a finite renderLimit for DoS protection (common in multi-tenant template-authoring environments) can still be forced by a single crafted template to monopolize a Node.js event-loop worker for attacker-controlled time, potentially stalling in-flight requests, with availability impact only. This issue has been fixed in version 10.26.0.
CVSS breakdown
Affected products
- harttle / liquidjs< 10.26.0 – < 10.26.0