CVE-2021-39222 XSS in Talk
Stored XSS in Nextcloud Talk allows code execution via malicious files, though mitigated by CSP on modern browsers.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2021-39222?
CVE-2021-39222 is a medium-severity cross-site scripting vulnerability in nextcloud security-advisories, published on 15 Nov 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Nextcloud is an open-source, self-hosted productivity platform. The Nextcloud Talk application was vulnerable to a stored Cross-Site Scripting (XSS) vulnerability. For exploitation, a user would need to right-click on a malicious file and open the file in a new tab. Due the strict Content-Security-Policy shipped with Nextcloud, this issue is not exploitable on modern browsers supporting Content-Security-Policy. It is recommended that the Nextcloud Talk application is upgraded to patched versions 10.0.7, 10.1.4, 11.1.2, 11.2.0 or 12.0.0. As a workaround, use a browser that has support for Content-Security-Policy.
Which versions are affected by CVE-2021-39222?
It affects 1 product.
Products include Nextcloud Talk.
How do I fix CVE-2021-39222?
No fix has been published for CVE-2021-39222 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-2021-39222 being exploited?
There is no known exploitation of CVE-2021-39222 in the wild and no public exploit code.
Other vulnerabilities in nextcloud security-advisories
- CVE-2020-8180 Code injection in Nextcloud Talk
- CVE-2021-32689 Nextcloud Talk not properly disassociating users from chats after account deletion
- CVE-2023-39957 Path traversal allows tricking the Talk Android app into writing files into it's root directory
- CVE-2021-32676 Session Fixation in Nextcloud Talk
- CVE-2018-3781 Cross-site scripting in nextcloud/talk
Sources
Also known as GHSA-xhxq-f4vg-jw5g.