kkFileView >= 4.2.0 is vulnerable to Server-Side Request Forgery (SSRF). The cross-origin file proxy endpoint /getCorsFile is protected by TrustHostFilter against the trust.host whitelist. However, the URL parameter validated by the filter is not the same parameter the controller actually fetches: the filter validates the first non-empty parameter in a fixed priority order, while the controller only reads and fetches urlPath. By supplying both urlPath=<real target> and url=<whitelisted decoy address> in the same request, the decoy passes validation while the unvalidated real target is fetched server-side — and the response body is echoed back to the attacker.

kkFileView v5.0.0 through v5.0.2 contains a directory traversal vulnerability in FileController.java. The fileUpload, createFolder and existsFile endpoints accept a "path" parameter that is concatenated into the upload base path without validation, allowing unauthenticated attackers to create arbitrary directories and write arbitrary files outside the intended fileDir root via a crafted multipart request

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.