CVE-2026-45283: Nextcloud: Files Lock app allows users to lock and unlock files of other users
Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.2, and 33.0.0 to before 33.0.1, the fileslock app did not properly validate the ownership of files when processing DAV lock and unlock requests. An authenticated user could lock or unlock files belonging to other users by targeting their absolute WebDAV paths. Additionally, lock tokens were disclosed to unauthorized callers in error responses, allowing attackers to remove token-based locks placed by other users' client applications. It is recommended that the Nextcloud Server is upgraded to 32.0.2 or 33.0.1. It is recommended that the Nextcloud Enterprise Server is upgraded to 31.0.14.4 or 32.0.2 or 33.0.1
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Nextcloud Serverto a version that resolves this vulnerability.Fixed in 31.0.14.4 - Upgrade
Upgrade
Nextcloud Serverto a version that resolves this vulnerability.Fixed in 32.0.2 - Upgrade
Upgrade
Nextcloud Serverto a version that resolves this vulnerability.Fixed in 33.0.1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-45283?
CVE-2026-45283 has a medium severity score of 6.3.
How do I fix CVE-2026-45283?
To fix CVE-2026-45283, you should patch your Nextcloud Server to versions 32.0.2 or 33.0.1 or later.
What type of vulnerability is CVE-2026-45283?
CVE-2026-45283 is a vulnerability in the Nextcloud Files Lock app that allows users to lock and unlock files owned by other users.
Which versions of Nextcloud are affected by CVE-2026-45283?
Nextcloud Server versions 32.0.0 to before 32.0.2 and 33.0.0 to before 33.0.1 are affected by CVE-2026-45283.
Who can exploit CVE-2026-45283?
Any authenticated user can exploit CVE-2026-45283 to lock or unlock files that belong to other users.