{"id":"CVE-2021-21316","aliases":["EUVD-2021-0483","GHSA-3crj-w4f5-gwh4"],"status":"published","title":"Arbitrary code execution in less-openui5","description":"less-openui5 is an npm package which enables building OpenUI5 themes with Less.js. In less-openui5 before version 0.10., when 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. While this is a feature of the Less.js library it is an unexpected behavior in the context of OpenUI5 and SAPUI5 development. Especially in the context of UI5 Tooling which relies on less-openui5. An attacker might create a library or theme-library containing a custom control or theme, hiding malicious JavaScript code in one of the .less files. Refer to the referenced GHSA-3crj-w4f5-gwh4 for examples. Starting with Less.js version 3.0.0, the Inline JavaScript feature is disabled by default. less-openui5 however currently uses a fork of Less.js v1.6.3. Note that disabling the Inline JavaScript feature in Less.js versions 1.x, still evaluates code has additional double codes around it. We decided to remove the inline JavaScript evaluation feature completely from the code of our Less.js fork. This fix is available in less-openui5 version 0.10.0.","severity":{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.01,"percentile":0.63281,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-74"],"published":"2021-01-29T20:51:37Z","modified":"2026-10-20T10:54:28Z","fixes":[{"ecosystem":"npm","package":"less-openui5","fixed_in":["0.10.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"less-openui5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.10.0"}]}]},{"source":"osv","ecosystem":"npm","package":"less-openui5","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.10.0"}]}]}],"products":[{"vendor":"less-openui5_project","product":"less-openui5"},{"vendor":"sap","product":"less-openui5"}],"references":[{"url":"https://github.com/SAP/less-openui5/security/advisories/GHSA-3crj-w4f5-gwh4","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory","advisory","web"]},{"url":"https://github.com/SAP/less-openui5/commit/c0d3a8572974a20ea6cee42da11c614a54f100e8","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://github.com/SAP/less-openui5/releases/tag/v0.10.0","tags":["x_refsource_MISC","x_transferred","Release Notes","Third Party Advisory","advisory","web"]},{"url":"https://www.npmjs.com/package/less-openui5","tags":["x_refsource_MISC","x_transferred","Product","Third Party Advisory","advisory","web"]},{"url":"http://lesscss.org/usage/#less-options-enable-inline-javascript-deprecated-","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21316","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-3crj-w4f5-gwh4"}],"sources":{"cve":[{"id":"CVE-2021-21316","title":"Arbitrary code execution in less-openui5","description":"less-openui5 is an npm package which enables building OpenUI5 themes with Less.js. In less-openui5 before version 0.10., when 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. While this is a feature of the Less.js library it is an unexpected behavior in the context of OpenUI5 and SAPUI5 development. Especially in the context of UI5 Tooling which relies on less-openui5. An attacker might create a library or theme-library containing a custom control or theme, hiding malicious JavaScript code in one of the .less files. Refer to the referenced GHSA-3crj-w4f5-gwh4 for examples. Starting with Less.js version 3.0.0, the Inline JavaScript feature is disabled by default. less-openui5 however currently uses a fork of Less.js v1.6.3. Note that disabling the Inline JavaScript feature in Less.js versions 1.x, still evaluates code has additional double codes around it. We decided to remove the inline JavaScript evaluation feature completely from the code of our Less.js fork. This fix is available in less-openui5 version 0.10.0.","status":"published","published":"2021-02-16T17:35:16Z","modified":"2024-08-03T18:09:15.881Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-74"],"updated_at":"2026-11-02T14:33:00.137099Z"}],"euvd":[{"id":"EUVD-2021-0483","description":"less-openui5 is an npm package which enables building OpenUI5 themes with Less.js. In less-openui5 before version 0.10., when 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. While this is a feature of the Less.js library it is an unexpected behavior in the context of OpenUI5 and SAPUI5 development. Especially in the context of UI5 Tooling which relies on less-openui5. An attacker might create a library or theme-library containing a custom control or theme, hiding malicious JavaScript code in one of the .less files. Refer to the referenced GHSA-3crj-w4f5-gwh4 for examples. Starting with Less.js version 3.0.0, the Inline JavaScript feature is disabled by default. less-openui5 however currently uses a fork of Less.js v1.6.3. Note that disabling the Inline JavaScript feature in Less.js versions 1.x, still evaluates code has additional double codes around it. We decided to remove the inline JavaScript evaluation feature completely from the code of our Less.js fork. This fix is available in less-openui5 version 0.10.0.","status":"published","published":"2021-02-16T17:35:16Z","modified":"2024-08-03T18:09:15Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N","level":"medium"}],"updated_at":"2026-11-03T03:25:06.913643Z"}],"ghsa":[{"id":"GHSA-3crj-w4f5-gwh4","title":"Processing untrusted theming resources might execute arbitrary code (ACE)","description":"### 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","status":"published","published":"2021-01-29T20:51:37Z","modified":"2023-02-01T05:05:10Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N","level":"medium"}],"cwes":["CWE-74"],"updated_at":"2026-11-02T14:36:32.918681Z"}],"nvd":[{"id":"CVE-2021-21316","description":"less-openui5 is an npm package which enables building OpenUI5 themes with Less.js. In less-openui5 before version 0.10., when 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. While this is a feature of the Less.js library it is an unexpected behavior in the context of OpenUI5 and SAPUI5 development. Especially in the context of UI5 Tooling which relies on less-openui5. An attacker might create a library or theme-library containing a custom control or theme, hiding malicious JavaScript code in one of the .less files. Refer to the referenced GHSA-3crj-w4f5-gwh4 for examples. Starting with Less.js version 3.0.0, the Inline JavaScript feature is disabled by default. less-openui5 however currently uses a fork of Less.js v1.6.3. Note that disabling the Inline JavaScript feature in Less.js versions 1.x, still evaluates code has additional double codes around it. We decided to remove the inline JavaScript evaluation feature completely from the code of our Less.js fork. This fix is available in less-openui5 version 0.10.0.","status":"published","published":"2021-02-16T18:15:12.49Z","modified":"2026-06-17T03:35:16.92Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"primary"},{"version":"2.0","score":6.8,"vector":"AV:N/AC:M/Au:N/C:P/I:P/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-74"],"updated_at":"2026-11-02T14:06:50.031227Z"}],"osv":[{"id":"CVE-2021-21316","description":"less-openui5 is an npm package which enables building OpenUI5 themes with Less.js. In less-openui5 before version 0.10., when 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. While this is a feature of the Less.js library it is an unexpected behavior in the context of OpenUI5 and SAPUI5 development. Especially in the context of UI5 Tooling which relies on less-openui5. An attacker might create a library or theme-library containing a custom control or theme, hiding malicious JavaScript code in one of the .less files. Refer to the referenced GHSA-3crj-w4f5-gwh4 for examples. Starting with Less.js version 3.0.0, the Inline JavaScript feature is disabled by default. less-openui5 however currently uses a fork of Less.js v1.6.3. Note that disabling the Inline JavaScript feature in Less.js versions 1.x, still evaluates code has additional double codes around it. We decided to remove the inline JavaScript evaluation feature completely from the code of our Less.js fork. This fix is available in less-openui5 version 0.10.0.","status":"published","published":"2021-02-16T18:15:12.49Z","modified":"2026-10-20T10:54:28.962988457Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T15:44:18.004149Z"},{"id":"GHSA-3crj-w4f5-gwh4","title":"Processing untrusted theming resources might execute arbitrary code (ACE)","description":"### 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","status":"published","published":"2021-01-29T20:51:37Z","modified":"2026-07-08T06:28:29.484614664Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N","level":"medium"}],"cwes":["CWE-74"],"updated_at":"2026-11-02T15:46:35.747385Z"}]}}