CVE-2020-7746 is a critical-severity (CVSS 9.8) CWE-1321 vulnerability in chart.js. 4 public exploit references exist, so weaponization risk is real. O3 Security confirms whether CVE-2020-7746 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Prototype pollution in chart.js
Real-World Exposure
chart.jsReal-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
This affects the package chart.js before 2.9.4. The options parameter is not properly sanitized when it is processed. When the options are processed, the existing options (or the defaults options) are deeply merged with provided options. However, during this operation, the keys of the object being set are not checked, leading to a prototype pollution.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | chart.js | all versions | 2.9.4 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
This affects the package chart.js before 2.9.4. The options parameter is…
This affects the package chart.js before 2.9.4. The options parameter is…
This affects the package chart.js before 2.9.4. The options parameter is…
This affects the package chart.js before 2.9.4. The options parameter is…
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for chart.js. 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 chart.js to 2.9.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-7746 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-2020-7746 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-2020-7746. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is CVE-2020-7746 in your dependencies?
O3 detects CVE-2020-7746 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.