kkFileView 5.0.0 through 5.0.2 allows reflected XSS via the /onlinePreview endpoint. The OnlinePreviewController passes the user-controlled page and kkagent request parameters to FreeMarker templates without sanitization, and the templates insert these values into raw JavaScript contexts.

kkFileView is a universal file online preview project based on Spring Boot. Prior to 5.0.1, the unauthenticated GET /addTask endpoint in kkFileView is omitted from TrustHostFilter and TrustDirFilter in server/src/main/java/cn/keking/config/WebConfig.java, allowing FileConvertQueueTask to fetch an attacker-selected URL after FileHandlerService#getFileAttribute uses the fullfilename parameter to force an OFFICE, COMPRESS, or CAD type. This issue is fixed in version 5.0.1.

A vulnerability was found in kkFileView 4.4.0. It has been classified as critical. This affects an unknown part of the file /fileUpload. The manipulation of the argument File leads to unrestricted upload. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.