OxiCloud 0.9.1 through 0.9.3 Incorrect Authorization via Share Ring Cookie

OxiCloud 0.9.1 through 0.9.3 contains an incorrect authorization vulnerability that allows anonymous visitors to keep share access after password protection is added. Attackers holding an existing oxi_shares share-ring cookie can request content via GET /api/files/{id} to read shared files or folder contents despite the new password.