Home/CVE/Nextcloud Server is a self hosted personal cloud system. In Nextcloud Server and Enterprise Server prior to 31.0.1, non-
CVE

CVE-2025-66547

Nextcloud Server is a self hosted personal cloud system. In Nextcloud Server and Enterprise Server prior to 31.0.1, non-

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.

MEDIUM · CVSS 4.3 EPSS 0.00025
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  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-639Authorization Bypass Through User-Controlled Key
▤

Affected Products & Versions

1
nextcloud server>= 31.0.0 and < 31.0.1
▣

Scoring & Timeline

4.3
MEDIUM · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD05 Dec 2025 · 05:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

5
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hq6c-r898-fgf2PatchVendor 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 RequiredVendor Advisory
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