CVE-2019-16216 Cross-site scripting in n/a
A logged-in user can upload malicious files to execute stored cross-site scripting attacks against other users on the Zulip server.
- 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-2019-16216?
CVE-2019-16216 is a medium-severity cross-site scripting vulnerability in n/a, published on 18 Sep 2019. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Zulip server before 2.0.5 incompletely validated the MIME types of uploaded files. A user who is logged into the server could upload files of certain types to mount a stored cross-site scripting attack on other logged-in users. On a Zulip server using the default local uploads backend, the attack is only effective against browsers lacking support for Content-Security-Policy such as Internet Explorer 11. On a Zulip server using the S3 uploads backend, the attack is confined to the origin of the configured S3 uploads hostname and cannot reach the Zulip server itself.
Weakness: CWE-79
Which versions are affected by CVE-2019-16216?
It affects 1 product.
Products include Zulip Zulip Server.
How do I fix CVE-2019-16216?
No fix has been published for CVE-2019-16216 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-2019-16216 being exploited?
There is no known exploitation of CVE-2019-16216 in the wild and no public exploit code.
Other vulnerabilities in n/a
- CVE-2019-18933 Information disclosure in n/a
- CVE-2020-15070 Code injection in n/a
- CVE-2017-0910 Missing authorization in Zulip Server
- CVE-2025-31478 Zulip Authentication Backend Configuration Bypass
- CVE-2023-33186 Cross-site scripting vulnerability in Zulip Server development branch via topic tooltip
Sources
Also known as GHSA-j2r8-2vxg-pxvh.