Medium severity · published Dec 5, 2025
CVE-2025-66547
Nextcloud Server users can modify tags on files that do not belong to them
4.3
CVSS
0.3%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 20% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SE
security-advisories · nextcloud
< 31.0.1 · source: vendor
NS
Nextcloud Server · Nextcloud
31.0.0 before 31.0.1; 31.0.0 before 31.0.1 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-66547
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-66547
Patch
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hq6c-r898-fgf2
Patch
https://github.com/nextcloud/server/commit/b44f1568f2dc97c746281d99e2342ad679e3d8a9
Issue Tracking
https://github.com/nextcloud/server/issues/51247
Issue Tracking
https://github.com/nextcloud/server/pull/51288
Permissions Required
https://hackerone.com/reports/3040887
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