Title: Nextcloud, Description: Nextcloud es una plataforma de colaboración de contenido de código abierto. En el Servidor Nextcloud desde las versiones 32.0.0 hasta antes de la 32.0.2, y de la 33.0.0 hasta antes de la 33.0.1, la aplicación files_lock no validaba correctamente la propiedad de los archivos al procesar solicitudes de bloqueo y desbloqueo DAV. Un usuario autenticado podía bloquear o desbloquear archivos pertenecientes a otros usuarios al apuntar a sus rutas WebDAV absolutas. Además, los tokens de bloqueo se revelaban a llamadores no autorizados en las respuestas de error, permitiendo a los atacantes eliminar bloqueos basados en tokens colocados por las aplicaciones cliente de otros usuarios. Se recomienda que el Servidor Nextcloud se actualice a la 32.0.2 o a la 33.0.1. Se recomienda que el Servidor Nextcloud Enterprise se actualice a la 31.0.14.4 o a la 32.0.2 o a la 33.0.1

{"timestamp":"2026-06-01T21:41:51.211198Z","id":"CVE-2026-45283","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}

[{"vendor":"nextcloud","product":"security-advisories","versions":[{"version":">= 32.0.0, < 32.0.2","status":"affected"},{"version":">= 33.0.0, < 33.0.1","status":"affected"}]}]

AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

OR
          *cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:* versions from (including) 32.0.0 up to (excluding) 32.0.2
          *cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:* versions from (including) 33.0.0 up to (excluding) 33.0.1

OR
          *cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:* versions from (including) 31.0.0 up to (excluding) 31.0.14.4
          *cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:* versions from (including) 32.0.0 up to (excluding) 32.0.2
          *cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:* versions from (including) 33.0.0 up to (excluding) 33.0.1

GitHub, Inc.: https://github.com/nextcloud/files_lock/pull/1007 Types: Issue Tracking, Patch

GitHub, Inc.: https://github.com/nextcloud/security-advisories/security/advisories/GHSA-4chh-6mhf-p4jj Types: Vendor Advisory

GitHub, Inc.: https://hackerone.com/reports/3301553# Types: Permissions Required

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 files_lock 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

AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

CWE-287

https://github.com/nextcloud/files_lock/pull/1007

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-4chh-6mhf-p4jj

https://hackerone.com/reports/3301553#