# CVE-2023-25820: Nextcloud Server and Enterprise Server missing brute force protection on password confirmation modal

> Attackers with a logged-in session can brute force passwords on the confirmation modal due to missing rate limiting, potentially taking over accounts.

- **Severity:** Medium 4.2 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 22 Mar 2023
- **Updated:** 25 Feb 2025
- **Also known as:** GHSA-36g6-wjx2-333x

## What is CVE-2023-25820?

CVE-2023-25820 is a medium-severity vulnerability in Nextcloud Nextcloud Server, published on 22 Mar 2023. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Nextcloud Server is the file server software for Nextcloud, a self-hosted productivity platform, and Nextcloud Enterprise Server is the enterprise version of the file server software. In Nextcloud Server versions 25.0.x prior to 25.0.5 and versions 24.0.x prior to 24.0.10 as well as Nextcloud Enterprise Server versions 25.0.x prior to 25.0.4, 24.0.x prior to 24.0.10, 23.0.x prior to 23.0.12.5, 22.x prior to 22.2.0.10, and 21.x prior to 21.0.9.10, when an attacker gets access to an already logged in user session they can then brute force the password on the confirmation endpoint. Nextcloud Server should upgraded to 24.0.10 or 25.0.4 and Nextcloud Enterprise Server should upgraded to 21.0.9.10, 22.2.10.10, 23.0.12.5, 24.0.10, or 25.0.4 to receive a patch. No known workarounds are available.

Weakness: CWE-307 (Improper Restriction of Excessive Authentication Attempts)

## Which versions are affected by CVE-2023-25820?

It affects 1 product.


Products: Nextcloud Nextcloud Server.

## How do I fix CVE-2023-25820?

No fix has been published for CVE-2023-25820 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-25820 being exploited?

There is no known exploitation of CVE-2023-25820 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-2023-25820 and fix it if it is affected.

What it is: CVE-2023-25820 is a medium-severity vulnerability in Nextcloud Nextcloud Server, published on 22 Mar 2023. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-25820 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-2023-25820/ (Markdown: https://insights.sbomify.com/CVE-2023-25820/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-25820
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-25820
- OSV: https://osv.dev/vulnerability/CVE-2023-25820

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-25820/
Summaries are generated and may contain mistakes; the official description above is the record.