CVE-2024-4023 Stored XSS in flatpressblog/flatpress
Attackers can execute arbitrary JavaScript via stored XSS in FlatPress by uploading malicious files, potentially stealing cookies and accessing same-origin content.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2024-4023?
CVE-2024-4023 is a high-severity cross-site scripting vulnerability in flatpressblog/flatpress, published on 20 Mar 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-79
Which versions are affected by CVE-2024-4023?
It affects 1 product.
Products include Flatpress Flatpress.
How do I fix CVE-2024-4023?
No fix has been published for CVE-2024-4023 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2024-4023 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-4023 exists.
Other vulnerabilities in flatpressblog/flatpress
Sources
Also known as GHSA-qv9p-39px-hfwc.