# CVE-2021-32657: Malicious user could break user administration page

> A malicious user can disrupt the user administration page, preventing administrators from managing users on the Nextcloud instance.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/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:** No
- **Published:** 1 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-fx62-q47f-f665

## What is CVE-2021-32657?

CVE-2021-32657 is a medium-severity denial of service vulnerability in Nextcloud Nextcloud Server, published on 1 Jun 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Nextcloud Server is a Nextcloud package that handles data storage. In versions of Nextcloud Server prior to 10.0.11, 20.0.10, and 21.0.2, a malicious user may be able to break the user administration page. This would disallow administrators to administrate users on the Nextcloud instance. The vulnerability is fixed in versions 19.0.11, 20.0.10, and 21.0.2. As a workaround, administrators can use the OCC command line tool to administrate the Nextcloud users.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2021-32657?

It affects 1 product.


Products: Nextcloud Nextcloud Server.

## How do I fix CVE-2021-32657?

No fix has been published for CVE-2021-32657 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-32657 being exploited?

There is no known exploitation of CVE-2021-32657 in the wild and no public exploit code.

## Other vulnerabilities in Nextcloud Nextcloud Server

- [CVE-2021-32802](https://insights.sbomify.com/CVE-2021-32802/): Preview generation used third-party library not suited for user-generated content in Nextcloud server (critical 9.3)
- [CVE-2023-26482](https://insights.sbomify.com/CVE-2023-26482/): Scope of workflow operations is not validated in nextcloud server (critical 9.1)
- [CVE-2018-3775](https://insights.sbomify.com/CVE-2018-3775/): Auth bypass in Nextcloud Server (high 8.8)
- [CVE-2023-35172](https://insights.sbomify.com/CVE-2023-35172/): Nextcloud Server password reset endpoint is not brute force protected (high 8.7)
- [CVE-2023-32320](https://insights.sbomify.com/CVE-2023-32320/): Nextcloud Server's brute force protection allows someone to send more requests than intended (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-32657 and fix it if it is affected.

What it is: CVE-2021-32657 is a medium-severity denial of service vulnerability in Nextcloud Nextcloud Server, published on 1 Jun 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-32657 in the wild and no public exploit code.

Affected product: Nextcloud Nextcloud Server. 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-2021-32657/ (Markdown: https://insights.sbomify.com/CVE-2021-32657/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-32657
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-32657
- OSV: https://osv.dev/vulnerability/CVE-2021-32657

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-32657/
Summaries are generated and may contain mistakes; the official description above is the record.