LiquidJS's `{% render %}` tag silently bypasses per-render `ownPropertyOnly:true` via `Context.spawn()`

{
  "id": "29dd80225adc7884bcb2a4950fce44eefd2e0fce2daae0aab51a08cc961052b8",
  "url": "https://osv.dev/vulnerability/GHSA-9x9p-qf8f-mvjg",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "LiquidJS's `{% render %}` tag silently bypasses per-render `ownPropertyOnly:true` via `Context.spawn()`",
    "summary": "## Summary `Context.spawn()` in liquidjs creates a child `Context` for the `{% render %}` tag but does not propagate the parent context's resolved `ownPropertyOnly` value. The new context re-derives `ownPropertyOnly` from `opts.ownPropertyOnly` (the instance-level option), silently discarding any `RenderOptions.ownPropertyOnly` override that was supplied to `parseAndRender()`. As a result, a developer who runs a Liquid instance with the backwards-compatible `ownPropertyOnly:false` and then locks down an untrusted render with `parseAndRender(..., { ownPropertyOnly: true })` still leaks prototype-chain properties from inside any `{% render %}` partial. This is a distinct exploit surface from the previously identified array-filter variants (`where`, `reject`, `group_by`, `find`, `find_index`, `has`) — the underlying root cause in `Context.spawn()` is shared, but `{% render %}` is a separately reachable sink that needs no filter usage. ## Details The bug is in `Context.spawn()`: ```ts // src/context/context.ts:105-114 public spawn (scope = {}) { return new Context(scope, this.opts, { sync: this.sync, globals: this.globals, strictVariables: this.strictVariables // <-- ownPropertyOnly is missing here }, { renderLimit: this.renderLimit, memoryLimit: this.memoryLimit }) } ``` The constructor resolves `ownPropertyOnly` as: ```ts // src/context/context.ts:47 this.ownPropertyOnly = renderOptions.ownPropertyOnly ?? opts.ownPropertyOnly ``` Because `spawn()` passes a `RenderOptions` objec",
    "evidence": "osv:GHSA-9x9p-qf8f-mvjg",
    "products": [
      {
        "name": {
          "value": "liquidjs",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "10.26.0",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "GHSA-9x9p-qf8f-mvjg",
      "aliases": [
        "CVE-2026-44646",
        "GHSA-9x9p-qf8f-mvjg"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "10.26.0"
                }
              ]
            }
          ],
          "package": {
            "name": "liquidjs",
            "purl": "pkg:npm/liquidjs",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-9x9p-qf8f-mvjg/GHSA-9x9p-qf8f-mvjg.json"
          }
        }
      ],
      "modified": "2026-10-27T15:15:07.984943744Z",
      "provider": "osv",
      "references": [
        "https://github.com/harttle/liquidjs/security/advisories/GHSA-9x9p-qf8f-mvjg",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-44646",
        "https://github.com/harttle/liquidjs/commit/dbbf6288030591bf6da28d8c1cce5a17bca97bb6",
        "https://github.com/harttle/liquidjs",
        "https://github.com/harttle/liquidjs/blob/v10.26.0/CHANGELOG.md",
        "https://github.com/harttle/liquidjs/releases/tag/v10.26.0"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-693"
        ],
        "severity": "MODERATE",
        "github_reviewed": true,
        "nvd_published_at": "2026-06-17T23:17:03Z",
        "github_reviewed_at": "2026-05-27T00:28:06Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-44646",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 462824,
  "published_at": "2026-05-27T00:28:06+00:00"
}