CVE-2025-66547
Nextcloud Server users can modify tags on files that do not belong to them
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.
INFO
Published Date :
Dec. 5, 2025, 5:16 p.m.
Last Modified :
Dec. 9, 2025, 4:31 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update Nextcloud Server to 31.0.1 or later.
- Apply vendor security patches immediately.
- Verify file tag access controls.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-66547.
| URL | Resource |
|---|---|
| https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hq6c-r898-fgf2 | Patch Vendor Advisory |
| https://github.com/nextcloud/server/commit/b44f1568f2dc97c746281d99e2342ad679e3d8a9 | Patch |
| https://github.com/nextcloud/server/issues/51247 | Issue Tracking |
| https://github.com/nextcloud/server/pull/51288 | Issue Tracking |
| https://hackerone.com/reports/3040887 | Permissions Required Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-66547 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-66547
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-66547 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-66547 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Dec. 09, 2025
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:* versions from (including) 31.0.0 up to (excluding) 31.0.1 *cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:* versions from (including) 31.0.0 up to (excluding) 31.0.1 Added Reference Type GitHub, Inc.: https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hq6c-r898-fgf2 Types: Patch, Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/nextcloud/server/commit/b44f1568f2dc97c746281d99e2342ad679e3d8a9 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/nextcloud/server/issues/51247 Types: Issue Tracking Added Reference Type GitHub, Inc.: https://github.com/nextcloud/server/pull/51288 Types: Issue Tracking Added Reference Type GitHub, Inc.: https://hackerone.com/reports/3040887 Types: Permissions Required, Vendor Advisory -
New CVE Received by [email protected]
Dec. 05, 2025
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N Added CWE CWE-639 Added Reference https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hq6c-r898-fgf2 Added Reference https://github.com/nextcloud/server/commit/b44f1568f2dc97c746281d99e2342ad679e3d8a9 Added Reference https://github.com/nextcloud/server/issues/51247 Added Reference https://github.com/nextcloud/server/pull/51288 Added Reference https://hackerone.com/reports/3040887