FlatPress CMS v1.3.1 1.3 was discovered to use insecure methods to store authentication data via the cookie's component.

A stored cross-site scripting (XSS) vulnerability exists in flatpressblog/flatpress version 1.3. When a user uploads a file with a .xsig extension and directly accesses this file, the server responds with a Content-type of application/octet-stream, leading to the file being processed as an HTML file. This allows an attacker to execute arbitrary JavaScript code, which can be used to steal user cookies, perform HTTP requests, and access content of the same origin.

FlatPress CMS version latest is vulnerable to Cross-Site Request Forgery (CSRF) attacks that allow an attacker to enable or disable plugins on behalf of a victim user. The attacker can craft a malicious link or script that, when clicked by an authenticated user, will send a request to the FlatPress CMS server to perform the desired action on behalf of the victim user. Since the request is authenticated, the server will process it as if it were initiated by the legitimate user, effectively allowing the attacker to perform unauthorized actions. This vulnerability is fixed in version 1.4.dev.

A vulnerability in the file upload functionality of the FlatPress CMS admin panel (version latest) allows an attacker to upload a file with a JavaScript payload disguised as a filename. This can lead to a Cross-Site Scripting (XSS) attack if the uploaded file is accessed by other users. The issue is fixed in version 1.4.dev.

A stored Cross-Site Scripting (XSS) vulnerability exists in the administration panel of Flatpress CMS before 1.4 via the gallery captions component. An attacker with admin privileges can inject a malicious JavaScript payload into the system, which is then stored persistently.