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.

CVSS 3.1

4.3CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS

0.3% chance of exploitation in the next 30 days; higher than 20% of CVEs (scores of 2026-10-25)

CWE

CWE-639

Published

2025-12-05

Modified

2026-10-18

Record from

the NVD, synced 2026-10-19

Affected

• nextcloud:nextcloud_server

References

• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hq6c-r898-fgf2
• https://github.com/nextcloud/server/commit/b44f1568f2dc97c746281d99e2342ad679e3d8a9
• https://github.com/nextcloud/server/issues/51247
• https://github.com/nextcloud/server/pull/51288
• https://hackerone.com/reports/3040887

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