Nextcloud Server users can modify tags on files that do not belong to them
CVE-2025-66547

4.3MEDIUM

Key Information:

Vendor

Nextcloud
Status
Security-advisories
Vendor
CVE Published:
5 December 2025

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.

Affected Version(s)

security-advisories < 31.0.1

References

https://github.com/nextcloud/security-advisories/security...
x_refsource_CONFIRM
https://github.com/nextcloud/server/issues/51247
x_refsource_MISC
https://github.com/nextcloud/server/pull/51288
x_refsource_MISC

CVSS V3.1

Score:
4.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

JSON
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CVE-2025-66547 : Privilege Escalation in Nextcloud Server Affects User File Tagging