CVE-2021-21316: Less openui5 Remote Code Execution Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-3crj-w4f5-gwh4",
  "modified" : "2021-02-16T17:35:25Z",
  "published" : "2021-01-29T20:51:37Z",
  "aliases" : [ "CVE-2021-21316" ],
  "summary" : "Processing untrusted theming resources might execute arbitrary code (ACE)",
  "details" : "### Impact\nWhen processing theming resources (i.e. `*.less` files) with less-openui5 that originate from an untrusted source, those resources might contain JavaScript code which will be executed in the context of the build process.\n\nWhile this is a [feature](http://lesscss.org/usage/#less-options-enable-inline-javascript-deprecated-) of the [Less.js library](https://github.com/less/less.js), it is an unexpected behavior in the context of OpenUI5 and SAPUI5 development.\n\nEspecially in the context of [UI5 Tooling](https://github.com/SAP/ui5-tooling), which relies on less-openui5, this poses a security threat:\n\nAn attacker might create a [library](https://sap.github.io/ui5-tooling/pages/Builder/#library) or [theme-library](https://sap.github.io/ui5-tooling/pages/Builder/#theme-library) containing a custom control or theme, hiding malicious JavaScript code in one of the `.less` files.\n\nThis is an example of inline JavaScript in a Less file:\n```less\n.rule {\n\t@var: `(function(){console.log('Hello from JavaScript'); process.exit(1);})()`;\n\tcolor: @var;\n}\n```\n\nStarting with Less.js version 3.0.0, the Inline JavaScript feature is disabled by default. less-openui5 however currently uses [a fork](https://github.com/SAP/less-openui5/tree/master/lib/thirdparty/less) of Less.js v1.6.3.\n\nNote that disabling the Inline JavaScript feature in Less.js versions 1.x, still evaluates code has additional double codes around it:\n```less\n.rule {\n\t@var: \"`(function(){console.log('Hello from JavaScript'); process.exit(1);})()`\";\n\tcolor: @var;\n}\n```\n\n### Patches\nWe decided to remove the inline JavaScript evaluation feature completely from the code of our Less.js fork.\n\nThis fix is available in less-openui5 version [v0.10.0](https://github.com/SAP/less-openui5/releases/tag/v0.10.0)\n\n### Workarounds\nOnly process trusted theming resources.\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in https://github.com/SAP/less-openui5\n* Email us at secure@sap.com",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "less-openui5"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.10.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/SAP/less-openui5/security/advisories/GHSA-3crj-w4f5-gwh4"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-21316"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/SAP/less-openui5/commit/c0d3a8572974a20ea6cee42da11c614a54f100e8"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/SAP/less-openui5/releases/tag/v0.10.0"
  }, {
    "type" : "WEB",
    "url" : "https://www.npmjs.com/package/less-openui5"
  }, {
    "type" : "WEB",
    "url" : "http://lesscss.org/usage/#less-options-enable-inline-javascript-deprecated-"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-74" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-01-29T20:50:46Z",
    "nvd_published_at" : "2021-02-16T18:15:00Z"
  }
}