CVE-2021-43817 Reflected Cross-Site-Scripting vulnerability in Collabora Online

High 8.2 Published 13 Dec 2021 Updated 4 Aug 2024

Attackers can inject scripts into Collabora Online iframes to steal user settings and session authentication tokens.

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-2021-43817?

CVE-2021-43817 is a high-severity cross-site scripting vulnerability in CollaboraOnline online, published on 13 Dec 2021. 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

Collabora Online is a collaborative online office suite based on LibreOffice technology. In affected versions a reflected XSS vulnerability was found in Collabora Online. An attacker could inject unescaped HTML into a variable as they created the Collabora Online iframe, and execute scripts inside the context of the Collabora Online iframe. This would give access to a small set of user settings stored in the browser, as well as the session's authentication token which was also passed in at iframe creation time. Users should upgrade to Collabora Online 6.4.16 or higher or Collabora Online 4.2.20 or higher. Collabora Online Development Edition 21.11 is not affected.

Weakness: CWE-79

Which versions are affected by CVE-2021-43817?

It affects 1 product.

Products include Collabora Online.

How do I fix CVE-2021-43817?

No fix has been published for CVE-2021-43817 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-2021-43817 being exploited?

There is no known exploitation of CVE-2021-43817 in the wild and no public exploit code.

Sources

Also known as GHSA-7f6h-v9mx-58q9.