CVE-2025-66547
Nextcloud Server users can modify tags on files that do not belong to them
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Nextcloud Server users can modify tags on files that do not belong to them
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.
- Record
CVE-2025-66547- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-639
- Updated
- 2026-11-02
EUVDEUVD-2025-201447
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.
- Record
EUVD-2025-201447- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
NVD
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.
- Record
CVE-2025-66547- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-639
- Updated
- 2026-11-02
OSV
Nextcloud Server users can modify tags on files that do not belong to them
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.
- Record
CVE-2025-66547- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-639
- Updated
- 2026-11-02
OSVBIT-nextcloud-2025-66547 No score
Nextcloud Server users can modify tags on files that do not belong to them
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.
- Record
BIT-nextcloud-2025-66547- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
nextcloudBitnami |
before 31.0.1 | 31.0.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-66547 is a medium vulnerability (CVSS 4.3) in Nextcloud Server, published December 5, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.30%, the 22nd percentile. Fixed in nextcloud 31.0.1.
References
github.com/nextcloud/security-advisories/security/advisories/GHSA-hq6c-r898-fgf2
hackerone.com/reports/3040887
nvd.nist.gov/vuln/detail/CVE-2025-66547