CVE-2025-66547

Name: CVE-2025-66547
Creator: NVD / NIST
Published: 2025-12-05T17:16:05.33+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.3/10EPSS 0.24%

Last modified Jun 17, 2026

CVE-2025-66547 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. 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. EPSS estimates a 0.24% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

4.3/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS Probability

0.24%

14.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-639

Affected Software

Vendor	Product	Versions
Nextcloud	Nextcloud Server	>= 31.0.0, < 31.0.1

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hq6c-r898-fgf2Patch, Vendor Advisory
https://github.com/nextcloud/server/commit/b44f1568f2dc97c746281d99e2342ad679e3d8a9Patch
https://github.com/nextcloud/server/issues/51247Issue Tracking
https://github.com/nextcloud/server/pull/51288Issue Tracking
https://hackerone.com/reports/3040887Permissions Required, Vendor Advisory

Timeline

Published: Dec 5, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-66547?

How severe is CVE-2025-66547?

CVE-2025-66547 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.24% probability of exploitation in the next 30 days.

How do I fix CVE-2025-66547?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-66547?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST