# CVE-2023-28645: Secure view can be bypassed by using internal API endpoint in Nextcloud richdocuments

> Attackers can bypass secure view restrictions in Nextcloud richdocuments via an unprotected internal API endpoint, allowing unauthorized document access.

- **Severity:** Medium 5.7 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/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:** No
- **Published:** 31 Mar 2023
- **Updated:** 11 Feb 2025
- **Also known as:** GHSA-95j6-p5cj-5hh5

## What is CVE-2023-28645?

CVE-2023-28645 is a medium-severity vulnerability in nextcloud security-advisories, published on 31 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 richdocuments is a Nextcloud app integrating the office suit Collabora Online. In affected versions the secure view feature of the rich documents app can be bypassed by using unprotected internal API endpoint of the rich documents app. It is recommended that the Nextcloud Office app (richdocuments) is upgraded to 8.0.0-beta.1, 7.0.2 or 6.3.2. Users unable to upgrade may mitigate the issue by taking steps to restrict the ability to download documents. This includes ensuring that the `WOPI configuration` is configured to only serve documents between Nextcloud and Collabora. It is highly recommended to define the list of Collabora server IPs as the allow list within the Office admin settings of Nextcloud.

Weakness: CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2023-28645?

It affects 1 product.


Products: Nextcloud Richdocuments.

## How do I fix CVE-2023-28645?

No fix has been published for CVE-2023-28645 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-28645 being exploited?

There is no known exploitation of CVE-2023-28645 in the wild and no public exploit code.

## Other vulnerabilities in nextcloud security-advisories

- [CVE-2021-37628](https://insights.sbomify.com/CVE-2021-37628/): File Drop can be bypassed using Richdocuments app in nextcloud (high 7.5)
- [CVE-2022-31024](https://insights.sbomify.com/CVE-2022-31024/): Federated editing allows iframing remote servers by default in richdocuments (medium 6.5)
- [CVE-2023-25150](https://insights.sbomify.com/CVE-2023-25150/): Document content of files can be obtained through Collabora for files of other users (medium 5.8)
- [CVE-2021-37629](https://insights.sbomify.com/CVE-2021-37629/): Lack of ratelimit on Richdocuments OCS endpoint in nextcloud (medium 5.3)
- [CVE-2021-39223](https://insights.sbomify.com/CVE-2021-39223/): File path disclosure of shared files in Richdocuments application (medium 4.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-28645 and fix it if it is affected.

What it is: CVE-2023-28645 is a medium-severity vulnerability in nextcloud security-advisories, published on 31 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-2023-28645 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-2023-28645/ (Markdown: https://insights.sbomify.com/CVE-2023-28645/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28645
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28645
- OSV: https://osv.dev/vulnerability/CVE-2023-28645

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28645/
Summaries are generated and may contain mistakes; the official description above is the record.