CVE-2023-1720 Bitrix24 Stored Cross-Site Scripting (XSS) via File Upload

Critical 9.6 Published 1 Nov 2023 Updated 5 Sep 2024

Authenticated attackers can execute arbitrary JavaScript or PHP code by uploading crafted HTML files due to missing MIME type headers.

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-2023-1720?

CVE-2023-1720 is a critical cross-site scripting vulnerability in Bitrix24, published on 1 Nov 2023. 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

Lack of mime type response header in Bitrix24 22.0.300 allows authenticated remote attackers to execute arbitrary JavaScript code in the victim's browser, and possibly execute arbitrary PHP code on the server if the victim has administrator privilege, via uploading a crafted HTML file through /desktop_app/file.ajax.php?action=uploadfile.

Weakness: CWE-434

Which versions are affected by CVE-2023-1720?

It affects 1 product.

Products include Bitrix24 Bitrix24.

How do I fix CVE-2023-1720?

No fix has been published for CVE-2023-1720 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-2023-1720 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-1720 exists.

Sources

Also known as GHSA-3f75-53r3-6ghw.