CVE-2021-21316

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.

Category

6.3
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.30%
Third-Party Advisory lesscss.org Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory npmjs.com
Affected: SAP less-openui5
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2021-21316?
CVE-2021-21316 has been scored as a medium severity vulnerability.
How to fix CVE-2021-21316?
To fix CVE-2021-21316, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-21316 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-21316 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-21316?
CVE-2021-21316 affects SAP less-openui5.
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