CVE-2025-66547
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-12-05

Last updated on: 2025-12-09

Assigner: GitHub, Inc.

Description
Nextcloud Server is a self hosted personal cloud system. In Nextcloud Server and Enterprise Server prior to 31.0.1, non-privileged users can modify tags on files they should not have access to via bulk tagging. This vulnerability is fixed in 31.0.1.
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Meta Information
Published
2025-12-05
Last Modified
2025-12-09
Generated
2026-06-16
AI Q&A
2025-12-05
EPSS Evaluated
2026-06-15
NVD
CVE-2025-66547
EUVD
EUVD-2025-201447
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
nextcloud nextcloud_server From 31.0.0 (inc) to 31.0.1 (exc)
nextcloud nextcloud_server From 31.0.0 (inc) to 31.0.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-639 The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
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Executive Summary

This vulnerability in Nextcloud Server and Enterprise Server prior to version 31.0.1 allows non-privileged users to modify tags on files they should not have access to by using bulk tagging. This means users without proper permissions can change metadata tags on files, potentially affecting file organization or access control.

Impact Analysis

The vulnerability can impact you by allowing unauthorized users to alter file tags, which may lead to confusion, misclassification, or improper handling of files. Although it does not allow direct access to file contents or cause data loss, it can undermine file management and integrity within the system.

Mitigation Strategies

Upgrade Nextcloud Server or Enterprise Server to version 31.0.1 or later, as this version contains the fix for the vulnerability allowing non-privileged users to modify tags on files they should not have access to.

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