# CVE-2023-28646: App lockout in nextcloud Android app can be bypassed via thirdparty apps

> An attacker with physical access can bypass the Nextcloud Android app lockout via third-party apps to view file metadata.

- **Severity:** Medium 4.4 (`CVSS:3.1/AV:P/AC:H/PR:L/UI:R/S:C/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:** Yes
- **Published:** 30 Mar 2023
- **Updated:** 11 Feb 2025
- **Also known as:** BIT-nextcloud-2023-28646, GHSA-c3rf-94h6-vj8v

## What is CVE-2023-28646?

CVE-2023-28646 is a medium-severity authentication bypass vulnerability in nextcloud security-advisories, published on 30 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 android is an android app for interfacing with the nextcloud home server ecosystem. In versions from 3.7.0 and before 3.24.1 an attacker that has access to the unlocked physical device can bypass the Nextcloud Android Pin/passcode protection via a thirdparty app. This allows to see meta information like sharer, sharees and activity of files. It is recommended that the Nextcloud Android app is upgraded to 3.24.1. There are no known workarounds for this vulnerability.

Weakness: CWE-287 (Improper Authentication), CWE-281 (Improper Preservation of Permissions)

## Which versions are affected by CVE-2023-28646?

1 open source package ship an affected version, including nextcloud. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `nextcloud` | Bitnami | From 3.7.0 | 3.24.1 |

Products: Nextcloud Nextcloud.

## How do I fix CVE-2023-28646?

Upgrade nextcloud to 3.24.1 or later.

## Is CVE-2023-28646 being exploited?

There is no known exploitation of CVE-2023-28646 in the wild and no public exploit code.

## Other vulnerabilities in nextcloud security-advisories

- [CVE-2019-5454](https://insights.sbomify.com/CVE-2019-5454/): SQL injection in com.nextcloud.client (critical 9.8)
- [CVE-2021-43863](https://insights.sbomify.com/CVE-2021-43863/): SQL Injection in FileContentProvider (GHSL-2021-1007) (high 7.5)
- [CVE-2019-5450](https://insights.sbomify.com/CVE-2019-5450/): Cross-site scripting in com.nextcloud.client (medium 6.8)
- [CVE-2019-5455](https://insights.sbomify.com/CVE-2019-5455/): Auth bypass in com.nextcloud.client (medium 6.8)
- [CVE-2021-22905](https://insights.sbomify.com/CVE-2021-22905/): Information disclosure in Nextcloud Android App (com.nextcloud.client) (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-28646 and fix it if it is affected.

What it is: CVE-2023-28646 is a medium-severity authentication bypass vulnerability in nextcloud security-advisories, published on 30 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-2023-28646 in the wild and no public exploit code.

Affected packages and fixed versions:
- nextcloud (Bitnami): affected from 3.7.0; fixed in 3.24.1

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-2023-28646/ (Markdown: https://insights.sbomify.com/CVE-2023-28646/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28646
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28646
- OSV: https://osv.dev/vulnerability/CVE-2023-28646

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28646/
Summaries are generated and may contain mistakes; the official description above is the record.