CVE-2021-41174
MEDIUMXSS vulnerability allowing arbitrary JavaScript execution
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
@grafana/dataReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
Grafana is an open-source platform for monitoring and observability. In affected versions if an attacker is able to convince a victim to visit a URL referencing a vulnerable page, arbitrary JavaScript content may be executed within the context of the victim's browser. The user visiting the malicious link must be unauthenticated and the link must be for a page that contains the login button in the menu bar. The url has to be crafted to exploit AngularJS rendering and contain the interpolation binding for AngularJS expressions. AngularJS uses double curly braces for interpolation binding: {{ }} ex: {{constructor.constructor(‘alert(1)’)()}}. When the user follows the link and the page renders, the login button will contain the original link with a query parameter to force a redirect to the login page. The URL is not validated and the AngularJS rendering engine will execute the JavaScript expression contained in the URL. Users are advised to upgrade as soon as possible. If for some reason you cannot upgrade, you can use a reverse proxy or similar to block access to block the literal string {{ in the path.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @grafana/data | ≥ 8.0.0&&< 8.2.3 | 8.2.3 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @grafana/data. 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 @grafana/data to 8.2.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41174 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 CVE-2021-41174 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 CVE-2021-41174. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2021-41174 in your dependencies?
O3 detects CVE-2021-41174 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.