GHSA-3crj-w4f5-gwh4 is a medium-severity (CVSS 6.3) CWE-74 vulnerability in less-openui5. O3 Security confirms whether GHSA-3crj-w4f5-gwh4 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Processing untrusted theming resources might execute arbitrary code (ACE)
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
less-openui5npmDescription
Impact
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, this poses a security threat:
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.
This is an example of inline JavaScript in a Less file:
.rule {
@var: `(function(){console.log('Hello from JavaScript'); process.exit(1);})()`;
color: @var;
}
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:
.rule {
@var: "`(function(){console.log('Hello from JavaScript'); process.exit(1);})()`";
color: @var;
}
Patches
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 v0.10.0
Workarounds
Only process trusted theming resources.
For more information
If you have any questions or comments about this advisory:
- Open an issue in https://github.com/SAP/less-openui5
- Email us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | less-openui5 | all versions | 0.10.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for less-openui5. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update less-openui5 to 0.10.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3crj-w4f5-gwh4 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-3crj-w4f5-gwh4 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-3crj-w4f5-gwh4. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-3crj-w4f5-gwh4 in your dependencies?
O3 detects GHSA-3crj-w4f5-gwh4 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.