# CVE-2021-42048: Cross-site scripting in n/a

> Administrators can inject arbitrary JavaScript into the Newcomer home page, allowing execution against new users and potential account takeover.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 6 Oct 2021
- **Updated:** 4 Aug 2024
- **Also known as:** BIT-mediawiki-2021-42048, GHSA-89h4-mq5m-6vvc

## What is CVE-2021-42048?

CVE-2021-42048 is a medium-severity cross-site scripting vulnerability in Mediawiki Mediawiki, published on 6 Oct 2021. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

An issue was discovered in the Growth extension in MediaWiki through 1.36.2. Any admin can add arbitrary JavaScript code to the Newcomer home page footer, which can be executed by viewers with zero edits.

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

## Which versions are affected by CVE-2021-42048?

1 open source package ship an affected version, including mediawiki. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mediawiki` | Bitnami | All versions | 1.36.3 |

Products: Mediawiki Mediawiki.

## How do I fix CVE-2021-42048?

Upgrade mediawiki to 1.36.3 or later.

## Is CVE-2021-42048 being exploited?

There is no known exploitation of CVE-2021-42048 in the wild and no public exploit code.

## Other vulnerabilities in Mediawiki Mediawiki

- [CVE-2023-37303](https://insights.sbomify.com/CVE-2023-37303/): Denial of service in n/a (critical 9.8)
- [CVE-2022-29904](https://insights.sbomify.com/CVE-2022-29904/): SQL injection in n/a (critical 9.8)
- [CVE-2022-29906](https://insights.sbomify.com/CVE-2022-29906/): Missing authorization in n/a (critical 9.8)
- [CVE-2022-28205](https://insights.sbomify.com/CVE-2022-28205/): Business logic in n/a (critical 9.8)
- [CVE-2022-28206](https://insights.sbomify.com/CVE-2022-28206/): Missing authorization in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-42048 and fix it if it is affected.

What it is: CVE-2021-42048 is a medium-severity cross-site scripting vulnerability in Mediawiki Mediawiki, published on 6 Oct 2021. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-42048 in the wild and no public exploit code.

Affected packages and fixed versions:
- mediawiki (Bitnami): affected all versions; fixed in 1.36.3

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-2021-42048/ (Markdown: https://insights.sbomify.com/CVE-2021-42048/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-42048
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-42048
- OSV: https://osv.dev/vulnerability/CVE-2021-42048

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-42048/
Summaries are generated and may contain mistakes; the official description above is the record.