# CVE-2023-23942: Self reflected HTML injection in Desktop client

> An attacker can inject JavaScript into the Nextcloud Desktop Client UI via unsanitized HTML labels, potentially executing arbitrary code.

- **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:** 6 Feb 2023
- **Updated:** 10 Mar 2025
- **Also known as:** DEBIAN-CVE-2023-23942, GHSA-64qc-vf6v-8xgg, UBUNTU-CVE-2023-23942

## What is CVE-2023-23942?

CVE-2023-23942 is a medium-severity cross-site scripting vulnerability in nextcloud security-advisories, published on 6 Feb 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

The Nextcloud Desktop Client is a tool to synchronize files from a Nextcloud Server with your computer. Versions prior to 3.6.3 are missing sanitisation on qml labels which are used for basic HTML elements such as `strong`, `em` and `head` lines in the UI of the desktop client. The lack of sanitisation may allow for javascript injection. It is recommended that the Nextcloud Desktop Client is upgraded to 3.6.3. There are no known workarounds for this issue.

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

## Which versions are affected by CVE-2023-23942?

It affects 1 product.


Products: Nextcloud Desktop.

## How do I fix CVE-2023-23942?

Upgrade to a fixed version.

## Is CVE-2023-23942 being exploited?

There is no known exploitation of CVE-2023-23942 in the wild and no public exploit code.

## Other vulnerabilities in nextcloud security-advisories

- [CVE-2024-46958](https://insights.sbomify.com/CVE-2024-46958/): Misconfiguration in n/a (critical 9.1)
- [CVE-2020-8224](https://insights.sbomify.com/CVE-2020-8224/): Code injection in Desktop Client (high 7.8)
- [CVE-2020-8225](https://insights.sbomify.com/CVE-2020-8225/): Information disclosure in Desktop Client (high 7.5)
- [CVE-2021-37617](https://insights.sbomify.com/CVE-2021-37617/): Untrusted Search Path in Nextcloud Desktop Client (high 7.3)
- [CVE-2023-28999](https://insights.sbomify.com/CVE-2023-28999/): Nextcloud: Lack of authenticity of metadata keys allows a malicious server to gain access to E2EE folders (medium 6.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-23942 and fix it if it is affected.

What it is: CVE-2023-23942 is a medium-severity cross-site scripting vulnerability in nextcloud security-advisories, published on 6 Feb 2023. 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-2023-23942 in the wild and no public exploit code.

Affected product: nextcloud security-advisories. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2023-23942/ (Markdown: https://insights.sbomify.com/CVE-2023-23942/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-23942
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-23942
- OSV: https://osv.dev/vulnerability/CVE-2023-23942

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-23942/
Summaries are generated and may contain mistakes; the official description above is the record.