CVE-2016-4567
MEDIUMCVE-2016-4567 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in mediaelement. O3 Security confirms whether CVE-2016-4567 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
MediaElement Vulnerable to Reflected XSS
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
mediaelementnpmDescription
Cross-site scripting (XSS) vulnerability in flash/FlashMediaElement.as in MediaElement.js before 2.21.0, as used in WordPress before 4.5.2, allows remote attackers to inject arbitrary web script or HTML via an obfuscated form of the jsinitfunction parameter, as demonstrated by "jsinitfunctio%gn."
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | mediaelement | all versions | 2.11.1 |
| 🐘Packagist | contao-components/mediaelement | ≥ 2.14.2&&< 2.21.1 | 2.21.1 |
| 🐘Packagist | contao/core | ≥ 3.0.0&&< 3.5.15 | 3.5.15 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mediaelement. 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 mediaelement to 2.11.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-4567 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-2016-4567 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-2016-4567. 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-2016-4567 in your dependencies?
O3 detects CVE-2016-4567 across npm, Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.