CVE-2023-49105
Description
An issue was discovered in ownCloud owncloud/core before 10.13.1. An attacker can access, modify, or delete any file without authentication if the username of a victim is known, and the victim has no signing-key configured. This occurs because pre-signed URLs can be accepted even when no signing-key is configured for the owner of the files. The earliest affected version is 10.6.0.
Summary dbcve.org
In ownCloud core before 10.13.1, pre-signed URLs for file access are accepted even when the file owner has no signing-key configured. An attacker with knowledge of a victim's username can access, modify, or delete any of that user's files without authentication by crafting pre-signed URLs, since the system fails to validate that a signing-key exists for the user before accepting the URL.
Mitigation
Upgrade ownCloud core to version 10.13.1 or later. Additionally, ensure all users have signing-keys configured as a defense-in-depth measure until the patch is applied.