CVE-2019-16769 — serialize-javascript
MEDIUMCVE-2019-16769 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in serialize-javascript. A fix is available for serialize-javascript — see the affected versions and patch details below.
Cross-Site Scripting in serialize-javascript
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.
How urgent is this, really
CVE-2019-16769 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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.
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 | 2.1.1npm install serialize-javascript@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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2019-16769 can be triaged on real exposure rather than presence alone.
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.
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.
In both OpenShift Container Platform (OCP) and OpenShift ServiceMesh (OSSM), the grafana and prometheus containers are behind OpenShift OAuth authentication. This restricts access to the vulnerable serialize-javascript library to authenticated users only, therefore the impact is low.
| Product | Fixed in | Advisory |
|---|---|---|
| OpenShift Service Mesh 1.1 | servicemesh-grafana-0:6.4.3-11.el8 | RHSA-2020:2796 |
| Red Hat OpenShift Container Platform 4.6 | openshift4/ose-grafana:v4.6.0-202010061132.p0 | RHSA-2020:4298 |
Frequently Asked Questions
Is CVE-2019-16769 in your dependencies?
O3 Security finds CVE-2019-16769 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.