CVE-2025-66547

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.

CVSS v3.1 Score

4.3

MEDIUM

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

Weakness Type (CWE)

CWE-639 CWE-639

Affected Products

Vendor	Product	Versions
nextcloud	nextcloud_server	31.0.0 — 31.0.1
nextcloud	nextcloud_server	31.0.0 — 31.0.1

References

Advisories & Patches

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hq6c-r898-fgf2 https://github.com/nextcloud/server/commit/b44f1568f2dc97c746281d99e2342ad679e3d8a9 https://hackerone.com/reports/3040887

Other References

https://github.com/nextcloud/server/issues/51247 https://github.com/nextcloud/server/pull/51288

Frequently Asked Questions

What is CVE-2025-66547? +

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. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2025-66547? +

CVE-2025-66547 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-66547? +

CVE-2025-66547 affects products from nextcloud, specifically: nextcloud_server. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-66547? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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