The password reset functionality in ownCloud Server before 8.1.11, 8.2.x before 8.2.9, 9.0.x before 9.0.7, and 9.1.x before 9.1.3 sends different error messages depending on whether the username is valid, which allows remote attackers to enumerate user names via a large number of password reset attempts.
Multiple unspecified vulnerabilities in the preview system in ownCloud 6.x before 6.0.6 and 7.x before 7.0.3 allow remote attackers to read arbitrary files via unknown vectors.
The SFTP external storage driver (files_external) in ownCloud Server before 6.0.5 validates the RSA Host key after login, which allows remote attackers to obtain sensitive information by sniffing the network.
An issue was discovered in ownCloud before 10.4. An attacker can bypass authentication on a password-protected image by displaying its preview.