CVE-2026-82980: Nextcloud Files Lock

Medium severity, CVSS 6.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Any authenticated user can lock or unlock files they do not own by targeting absolute WebDAV paths of other users. The DAV plugin resolves files from the absolute request URI without verifying that the path segment matches the authenticated session user. This enables: Cross-user manual locks : attacker locks a victim's files, blocking writes (PUT/MOVE/DELETE, editor saves). Lock-token disclosure: the app returns the lock token to unauthorized callers, enabling them to remove token-based locks (client locks) of other users.

Affected products

• Nextcloud Files Lock: from 31.0.0, up to and including 33.0.0

Published 2026-09-18. Last modified 2026-09-18.