# CVE-2023-28847: Nextcloud Server missing brute force protection for passwords of password protected share links

> Attackers can brute force passwords for protected share links due to missing rate limiting, potentially gaining unauthorized access to shared files.

- **Severity:** Low 3.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 25 Apr 2023
- **Updated:** 3 Feb 2025
- **Also known as:** GHSA-r5wf-xj97-3w7w

## What is CVE-2023-28847?

CVE-2023-28847 is a low-severity vulnerability in Nextcloud Nextcloud Server, published on 25 Apr 2023. An attacker can exploit it over the internet without logging in, 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. In Nextcloud Server 24.0.0 prior to 24.0.11 and 25.0.0 prior to 25.0.5; as well as Nextcloud Server Enterprise 23.0.0 prior to 23.0.12.6, 24.0.0 prior to 24.0.11, and 25.0.0 prior to 25.0.5; an attacker is not restricted in verifying passwords of share links so they can just start brute forcing the password. Nextcloud Server 24.0.11 and 25.0.5 and Nextcloud Enterprise Server 23.0.12.6, 24.0.11, and 25.0.5 contain a fix for this issue. No known workarounds are available.

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

## Which versions are affected by CVE-2023-28847?

It affects 1 product.


Products: Nextcloud Nextcloud Server.

## How do I fix CVE-2023-28847?

No fix has been published for CVE-2023-28847 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-28847 being exploited?

There is no known exploitation of CVE-2023-28847 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-2023-28847 and fix it if it is affected.

What it is: CVE-2023-28847 is a low-severity vulnerability in Nextcloud Nextcloud Server, published on 25 Apr 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-28847 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-2023-28847/ (Markdown: https://insights.sbomify.com/CVE-2023-28847/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28847
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28847
- OSV: https://osv.dev/vulnerability/CVE-2023-28847

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28847/
Summaries are generated and may contain mistakes; the official description above is the record.