CVE-2021-21316

Arbitrary code execution in less-openui5

HIGH
7.8
CVSS Score
Published: February 16, 2021 at 05:35 PM UTC
Updated: June 17, 2026 at 03:35 AM UTC
2 products affected across 2 vendorsLess OPENUI5OPENUI5 Project Less OPENUI5

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Severity
HIGH7.8
Exploit prediction
EPSS 1.0%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.10.0
Affected range stops below 0.10.0, so it looks safe — our inference, not a vendor statement
v < 0.10.0
Affected range stops below 0.10.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-74

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