# CVE-2021-3137: Cross Site Scripting (XSS) in XWiki

> Attackers can execute arbitrary scripts in victim browsers by uploading malicious SVG files to the comment section of XWiki.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 20 Jan 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-43hg-g44q-474q

## What is CVE-2021-3137?

CVE-2021-3137 is a medium-severity cross-site scripting vulnerability in Xwiki Xwiki, published on 20 Jan 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

XWiki 12.10.2 allows XSS via an SVG document to the upload feature of the comment section.

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

## Which versions are affected by CVE-2021-3137?

2 open source packages ship an affected version, including org.xwiki.commons:xwiki-commons. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.xwiki.commons:xwiki-commons` | Maven | All versions | 12.10.3 |
| `org.xwiki.commons:xwiki-commons` | Maven | All versions | 12.10.3 |

Products: Xwiki Xwiki.

## How do I fix CVE-2021-3137?

Upgrade org.xwiki.commons:xwiki-commons to 12.10.3 or later.

## Is CVE-2021-3137 being exploited?

There is no known exploitation of CVE-2021-3137 in the wild and no public exploit code.

## Other vulnerabilities in Xwiki Xwiki

- [CVE-2025-24893](https://insights.sbomify.com/CVE-2025-24893/): XWiki Platform Eval Injection (critical 9.8, exploited in the wild)
- [CVE-2025-53836](https://insights.sbomify.com/CVE-2025-53836/): XWiki Rendering is vulnerable to RCE attacks when processing nested macros (critical 10.0)
- [CVE-2024-55662](https://insights.sbomify.com/CVE-2024-55662/): XWiki allows remote code execution through the extension sheet (critical 10.0)
- [CVE-2024-55877](https://insights.sbomify.com/CVE-2024-55877/): XWiki allows remote code execution from account through macro descriptions and XWiki.XWikiSyntaxMacrosList (critical 10.0)
- [CVE-2024-37901](https://insights.sbomify.com/CVE-2024-37901/): XWiki Platform vulnerable to remote code execution from account via SearchSuggestConfigSheet (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3137 and fix it if it is affected.

What it is: CVE-2021-3137 is a medium-severity cross-site scripting vulnerability in Xwiki Xwiki, published on 20 Jan 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-3137 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.xwiki.commons:xwiki-commons (Maven): affected all versions; fixed in 12.10.3
- org.xwiki.commons:xwiki-commons (Maven): affected all versions; fixed in 12.10.3

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-2021-3137/ (Markdown: https://insights.sbomify.com/CVE-2021-3137/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3137
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3137
- OSV: https://osv.dev/vulnerability/CVE-2021-3137

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3137/
Summaries are generated and may contain mistakes; the official description above is the record.