How severe is CVE-2019-16769?

CVE-2019-16769 has a CVSS score of 5.4/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2019-16769?

CVE-2019-16769 affects the following packages: serialize-javascript (npm). Ecosystems affected: npm.

How do I fix CVE-2019-16769?

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.

How do I detect CVE-2019-16769 in my npm dependencies?

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.

How do I mitigate CVE-2019-16769 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2019-16769 actively exploited in the wild?

No public exploit code has been indexed for CVE-2019-16769 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2019-16769?

CVE-2019-16769 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 57th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2019-16769?

CVE-2019-16769 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2019-16769 published, and has it been updated?

CVE-2019-16769 was published on December 5, 2019 and was last updated on October 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

MEDIUM severity

CVE-2019-16769 — serialize-javascript

MEDIUM

CVE-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

Also known asGHSA-h9rv-jmmf-4pgx

Published

Dec 5, 2019

Updated

Oct 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs57th percentile — riskier than 57% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

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.

2Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

serialize-javascriptnpm

58.9Mdownloads / week

Description

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

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`serialize-javascript`	all versions	2.1.1`npm install serialize-javascript@2.1.1`

Affected Products

1 product · 1 configurations

Application

serialize-javascriptverizon

< 2.1.1

range

Detection & mitigation playbook

Open-source dependency

Detect
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
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

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.

Red HatModerate

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

O3 Security · Impact-Aware SCA

Is CVE-2019-16769 in your dependencies?

Find it across npm, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

5.4/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

CWE Classification

CWE-79Cross-site Scripting (XSS)

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

OpenSSF Scorecard

Package health score

serialize-javascript

5.2/10

Maintained10/10

Code-Review2/10

Branch-Protection3/10

Assessed Nov 2, 2026

Timeline

Disclosed

Dec 5, 2019

Last updated

Oct 20, 2026

Identifiers

CVE-2019-16769

GHSA-h9rv-jmmf-4pgx

References

Advisorygithub.com · GHSA h9rv jmmf 4pgx Advisorynvd.nist.gov · CVE 2019 16769 Advisorygithub.com · GHSA h9rv jmmf 4pgx Webnpmjs.com

Related vulnerabilities

Also affects serialize-javascript

This CVE is medium severity; 4 of 6 other CVEs affecting serialize-javascript are rated as high or higher (top: high).

CVE-2026-115897CVE-2026-97711CVE-2026-34043GHSA-5c6j-r48x-rmvqCVE-2024-11831CVE-2020-7660

Same weakness: CWE-79

This CVE is medium severity; 1 of 2 other CVEs with CWE-79 is rated as high or higher (top: moderate).

CVE-2026-126075CVE-2026-126063Browse all CWE-79

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 20, 2026