Nextcloud Server: External Storage Deletion (files_external) CVE-2023-39962
CVE-2023-39962 Published on August 10, 2023
Users can delete external storage mount points
Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 19.0.0 and prior to versions 19.0.13.10, 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.8, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1, a malicious user could delete any personal or global external storage, making them inaccessible for everyone else as well. Nextcloud server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 19.0.13.10, 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.9, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. As a workaround, disable app files_external. This also makes the external storage inaccessible but retains the configurations until a patched version has been deployed.
Vulnerability Analysis
CVE-2023-39962 is exploitable with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2023-39962. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is an Authorization Vulnerability?
The software does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
CVE-2023-39962 has been classified to as an Authorization vulnerability or weakness.
Products Associated with CVE-2023-39962
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Affected Versions
nextcloud security-advisories:- Version >= 19.0.0, < 19.0.13.10 is affected.
- Version >= 20.0.0, < 20.0.14.15 is affected.
- Version >= 21.0.0, < 21.0.9.13 is affected.
- Version >= 22.0.0, < 22.2.10.14 is affected.
- Version >= 23.0.0, < 23.0.12.9 is affected.
- Version >= 24.0.0, < 24.0.12.5 is affected.
- Version >= 25.0.0, < 25.0.9 is affected.
- Version >= 26.0.0, < 26.0.4 is affected.
- Version >= 27.0.0, < 27.0.1 is affected.
- Version 19.0.0 and below 19.0.13.0 is affected.
- Version 20.0.0 and below 20.0.14.15 is affected.
- Version 21.0.0 and below 21.0.9.13 is affected.
- Version 22.0.0 and below 22.2.10.14 is affected.
- Version 23.0.0 and below 23.0.12.9 is affected.
- Version 24.0.0 and below 24.0.12.5 is affected.
- Version 25.0.0 and below 25.0.9 is affected.
- Version 26.0.0 and below 26.0.4 is affected.
- Version 27.0.0 and below 27.0.1 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.