CVE-2019-16769
MEDIUMCVE-2019-16769 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in serialize-javascript. O3 Security confirms whether CVE-2019-16769 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Cross-Site Scripting in serialize-javascript
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
serialize-javascriptnpmDescription
The serialize-javascript npm package before version 2.1.1 is vulnerable to Cross-site Scripting (XSS). It does not properly mitigate against unsafe characters in serialized regular expressions. This vulnerability is not affected on Node.js environment since Node.js's implementation of RegExp.prototype.toString() backslash-escapes all forward slashes in regular expressions. If serialized data of regular expression objects are used in an environment other than Node.js, it is affected by this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | serialize-javascript | all versions | 2.1.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for serialize-javascript. 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 serialize-javascript to 2.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-16769 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-2019-16769 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-2019-16769. 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-2019-16769 in your dependencies?
O3 detects CVE-2019-16769 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.