CVE-2023-48239: Nextcloud Server users can make external storage mount points inaccessible for other users
First published: Tue Nov 21 2023(Updated: )
Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 25.0.0 and prior to versions 25.0.13, 26.0.8, and 27.1.3 of Nextcloud Server and starting in version 20.0.0 and prior to versions 20.0.14.16, 21.0.9.13, 22.2.10.15, 23.0.12.12, 24.0.12.8, 25.0.13, 26.0.8, and 27.1.3 of Nextcloud Enterprise Server, a malicious user could update any personal or global external storage, making them inaccessible for everyone else as well. Nextcloud Server 25.0.13, 26.0.8, and 27.1.3 and Nextcloud Enterprise Server is upgraded to 20.0.14.16, 21.0.9.13, 22.2.10.15, 23.0.12.12, 24.0.12.8, 25.0.13, 26.0.8, and 27.1.3 contain a patch for this issue. As a workaround, disable app files_external. This workaround also makes the external storage inaccessible but retains the configurations until a patched version has been deployed.
Credit: security-advisories@github.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Nextcloud Nextcloud Server | >=20.0.0<20.0.14.16 | |
| Nextcloud Nextcloud Server | >=21.0.0<21.0.9.13 | |
| Nextcloud Nextcloud Server | >=22.0.0<22.2.10.15 | |
| Nextcloud Nextcloud Server | >=23.0.0<23.0.12.12 | |
| Nextcloud Nextcloud Server | >=24.0.0<24.0.12.8 | |
| Nextcloud Nextcloud Server | >=25.0.0<25.0.13 | |
| Nextcloud Nextcloud Server | >=25.0.0<25.0.13 | |
| Nextcloud Nextcloud Server | >=26.0.0<26.0.8 | |
| Nextcloud Nextcloud Server | >=26.0.0<26.0.8 | |
| Nextcloud Nextcloud Server | >=27.0.0<27.1.3 | |
| Nextcloud Nextcloud Server | >=27.0.0<27.1.3 |
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Reference Links
Frequently Asked Questions
What is the vulnerability ID?
The vulnerability ID is CVE-2023-48239.
What is the severity of CVE-2023-48239?
The severity of CVE-2023-48239 is high with a CVSS score of 8.5.
Which software versions are affected by CVE-2023-48239?
Nextcloud Server versions 20.0.0 to 20.0.14.16, 21.0.0 to 21.0.9.13, 22.0.0 to 22.2.10.15, 23.0.0 to 23.0.12.12, 24.0.0 to 24.0.12.8, 25.0.0 to 25.0.13, 26.0.0 to 26.0.8, and 27.0.0 to 27.1.3 are affected by CVE-2023-48239.
How can Nextcloud Server users exploit this vulnerability?
Nextcloud Server users can make external storage mount points inaccessible for other users.
Are there any references related to CVE-2023-48239?
Yes, you can find references related to CVE-2023-48239 at the following links: [GitHub Security Advisory](https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f962-hw26-g267), [GitHub Pull Request](https://github.com/nextcloud/server/pull/41123), and [HackerOne Report](https://hackerone.com/reports/2212627).
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- vendor/nextcloud
- canonical/nextcloud nextcloud server
- version/nextcloud nextcloud server/20.0.0
- version/nextcloud nextcloud server/21.0.0
- version/nextcloud nextcloud server/22.0.0
- version/nextcloud nextcloud server/23.0.0
- version/nextcloud nextcloud server/24.0.0
- version/nextcloud nextcloud server/25.0.0
- version/nextcloud nextcloud server/26.0.0
- version/nextcloud nextcloud server/27.0.0