How severe is GHSA-h9rv-jmmf-4pgx?

GHSA-h9rv-jmmf-4pgx has a CVSS score of 4.2/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-h9rv-jmmf-4pgx?

GHSA-h9rv-jmmf-4pgx affects the following packages: serialize-javascript (npm). Ecosystems affected: npm.

How do I fix GHSA-h9rv-jmmf-4pgx?

Update serialize-javascript to 2.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h9rv-jmmf-4pgx is resolved across your whole dependency graph.

How do I detect GHSA-h9rv-jmmf-4pgx 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 GHSA-h9rv-jmmf-4pgx 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 GHSA-h9rv-jmmf-4pgx actively exploited in the wild?

No public exploit code has been indexed for GHSA-h9rv-jmmf-4pgx 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 GHSA-h9rv-jmmf-4pgx?

GHSA-h9rv-jmmf-4pgx 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 GHSA-h9rv-jmmf-4pgx?

GHSA-h9rv-jmmf-4pgx 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 GHSA-h9rv-jmmf-4pgx published, and has it been updated?

GHSA-h9rv-jmmf-4pgx was published on December 5, 2019 and was last updated on September 10, 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

Cross-Site Scripting in serialize-javascriptGHSA-h9rv-jmmf-4pgx

MEDIUM

GHSA-h9rv-jmmf-4pgx is a medium-severity (CVSS 4.2) Cross-site Scripting (XSS) vulnerability in serialize-javascript. A fix is available for serialize-javascript — see the affected versions and patch details below.

Also known asCVE-2019-16769

Published

Dec 5, 2019

Updated

Sep 10, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 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

58.2Mdownloads / 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 GHSA-h9rv-jmmf-4pgx 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

Versions of `serialize-javascript` prior to 2.1.1 are vulnerable to Cross-Site Scripting (XSS). The package fails to sanitize serialized regular expressions. This vulnerability does not affect Node.js applications. ## Recommendation Upgrade to version 2.1.1 or later.

O3 Security · Impact-Aware SCA

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Find it across npm, including transitive dependencies.

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CVSS Score

4.2/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

High

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

Low

Raw vector

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

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

Sep 10, 2026

Identifiers

GHSA-h9rv-jmmf-4pgx

References

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

Related vulnerabilities

Also affects serialize-javascript

This CVE is medium severity; 5 of 7 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-2020-7660CVE-2019-16769

Same weakness: CWE-79

This CVE is medium severity, in line with the other 1 CVE with CWE-79.

CVE-2026-126075Browse all CWE-79

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedSep 10, 2026