# CVE-2019-16772: regular expressions Cross-Site Scripting (XSS) vulnerability in serialize-to-js

> An attacker can inject malicious scripts via serialized regular expressions in serialize-to-js when used in non-Node.js environments.

- **Severity:** Low 3.1 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Dec 2019
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-3fjq-93xj-3f3f

## What is CVE-2019-16772?

CVE-2019-16772 is a low-severity cross-site scripting vulnerability in commenthol serialize-to-js, published on 6 Dec 2019. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The serialize-to-js NPM package before version 3.0.1 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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2019-16772?

2 open source packages ship an affected version, including serialize-to-js. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `serialize-to-js` | npm | All versions | 3.0.1 |
| `serialize-to-js` | npm | All versions | 3.0.1 |

Products: Serialize-to-Js Project Serialize-to-Js.

## How do I fix CVE-2019-16772?

Upgrade serialize-to-js to 3.0.1 or later.

## Is CVE-2019-16772 being exploited?

There is no known exploitation of CVE-2019-16772 in the wild and no public exploit code.

## Other vulnerabilities in commenthol serialize-to-js

- [CVE-2017-5954](https://insights.sbomify.com/CVE-2017-5954/): Code Execution Through IIFE in serialize-to-js (critical 9.8)
- [CVE-2017-15871](https://insights.sbomify.com/CVE-2017-15871/): Denial of service in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-16772 and fix it if it is affected.

What it is: CVE-2019-16772 is a low-severity cross-site scripting vulnerability in commenthol serialize-to-js, published on 6 Dec 2019. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-16772 in the wild and no public exploit code.

Affected packages and fixed versions:
- serialize-to-js (npm): affected all versions; fixed in 3.0.1
- serialize-to-js (npm): affected all versions; fixed in 3.0.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2019-16772/ (Markdown: https://insights.sbomify.com/CVE-2019-16772/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-16772
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-16772
- OSV: https://osv.dev/vulnerability/CVE-2019-16772

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-16772/
Summaries are generated and may contain mistakes; the official description above is the record.