Vulnerability · Published Dec 5, 2025 · Assigned by GitHub_M
CVE-2025-66547Nextcloud Server users can modify tags on files that do not belong to them
Medium 4.3
In plain English
A medium-severity authorization bypass via user-controlled key in security-advisories from nextcloud. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities).
Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.3%top 77.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| nextcloud | security-advisories | < 31.0.1 |
Weakness: CWE-639 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
References
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hq6c-r898-fgf2 x_refsource_CONFIRM
- https://github.com/nextcloud/server/issues/51247 x_refsource_MISC
- https://github.com/nextcloud/server/pull/51288 x_refsource_MISC
- https://github.com/nextcloud/server/commit/b44f1568f2dc97c746281d99e2342ad679e3d8a9 x_refsource_MISC
- https://hackerone.com/reports/3040887 x_refsource_MISC