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Users can modify tags on files that do not belong to them

Moderate
nickvergessen published GHSA-hq6c-r898-fgf2 Dec 5, 2025

Package

Server (Nextcloud)

Affected versions

31.0.0

Patched versions

31.0.1
Server (Nextcloud Enterprise)
31.0.0
31.0.1

Description

Impact

Non-privileged users can modify tags on files they should not have access to via bulk tagging.

Patches

It is recommended that the Nextcloud Server is upgraded to 31.0.1.
It is recommended that the Nextcloud Enterprise Server is upgraded to 31.0.1.

Workarounds

  • No workaround available

References

For more information

If you have any questions or comments about this advisory:

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CVE ID

CVE-2025-66547

Weaknesses

Authorization Bypass Through User-Controlled Key

The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. Learn more on MITRE.