# CVE-2023-28643: Potential share collision for recipients when caching is enabled in nextcloud server

> Attackers can overwrite shared folders with same-named shares when caching is enabled, causing data loss or confusion for recipients.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:N/AC:L/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:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 30 Mar 2023
- **Updated:** 11 Feb 2025
- **Also known as:** GHSA-hhq4-4pr8-wm27

## What is CVE-2023-28643?

CVE-2023-28643 is a medium-severity vulnerability in Nextcloud Nextcloud Server, published on 30 Mar 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

Nextcloud server is an open source home cloud implementation. In affected versions when a recipient receives 2 shares with the same name, while a memory cache is configured, the second share will replace the first one instead of being renamed to `{name} (2)`. It is recommended that the Nextcloud Server is upgraded to 25.0.3 or 24.0.9. Users unable to upgrade should avoid sharing 2 folders with the same name to the same user.

Weakness: CWE-706 (Use of Incorrectly-Resolved Name or Reference)

## Which versions are affected by CVE-2023-28643?

It affects 1 product.


Products: Nextcloud Nextcloud Server.

## How do I fix CVE-2023-28643?

No fix has been published for CVE-2023-28643 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-28643 being exploited?

There is no known exploitation of CVE-2023-28643 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-2023-28643 and fix it if it is affected.

What it is: CVE-2023-28643 is a medium-severity vulnerability in Nextcloud Nextcloud Server, published on 30 Mar 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-2023-28643 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-2023-28643/ (Markdown: https://insights.sbomify.com/CVE-2023-28643/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28643
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28643
- OSV: https://osv.dev/vulnerability/CVE-2023-28643

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28643/
Summaries are generated and may contain mistakes; the official description above is the record.