# CVE-2023-0842: xml2js 0.4.23 - Prototype Pollution

> An attacker can modify object properties via prototype pollution in the xml2js library by sending crafted JSON keys.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 5 Apr 2023
- **Updated:** 3 Dec 2025
- **Also known as:** CLSA-2026-1773879452, CLSA-2026-1773879453, CLSA-2026-1773879454, CLSA-2026-1777336771, DEBIAN-CVE-2023-0842, DLA-3760-1, GHSA-776f-qx25-q3cc, MINI-c4m6-75h7-69h3, MINI-jhw9-83cq-vccp, UBUNTU-CVE-2023-0842

## What is CVE-2023-0842?

CVE-2023-0842 is a medium-severity vulnerability in xml2js, published on 5 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

xml2js version 0.4.23 allows an external attacker to edit or add new properties to an object. This is possible because the application does not properly validate incoming JSON keys, thus allowing the __proto__ property to be edited.

Weakness: CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes)

## Which versions are affected by CVE-2023-0842?

2 open source packages ship an affected version, including xml2js. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `xml2js` | npm | All versions | 0.5.0 |
| `xml2js` | npm | All versions | 0.5.0 |

Products: Xml2js Project Xml2js.

## How do I fix CVE-2023-0842?

Upgrade xml2js to 0.5.0 or later.

## Is CVE-2023-0842 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-0842 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-0842 and fix it if it is affected.

What it is: CVE-2023-0842 is a medium-severity vulnerability in xml2js, published on 5 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-0842 exists.

Affected packages and fixed versions:
- xml2js (npm): affected all versions; fixed in 0.5.0
- xml2js (npm): affected all versions; fixed in 0.5.0

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-2023-0842/ (Markdown: https://insights.sbomify.com/CVE-2023-0842/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-0842
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-0842
- OSV: https://osv.dev/vulnerability/CVE-2023-0842

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-0842/
Summaries are generated and may contain mistakes; the official description above is the record.