CVE-2019-16215 Denial of service in n/a
A logged-in user can cause a denial of service in the Zulip server by sending a crafted message that triggers exponential backtracking in the Markdown parser.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2019-16215?
CVE-2019-16215 is a medium-severity denial of service vulnerability in n/a, published on 18 Sep 2019. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
The Markdown parser in Zulip server before 2.0.5 used a regular expression vulnerable to exponential backtracking. A user who is logged into the server could send a crafted message causing the server to spend an effectively arbitrary amount of CPU time and stall the processing of future messages.
Weakness: CWE-1333
Which versions are affected by CVE-2019-16215?
It affects 1 product.
Products include Zulip Zulip Server.
How do I fix CVE-2019-16215?
No fix has been published for CVE-2019-16215 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2019-16215 being exploited?
There is no known exploitation of CVE-2019-16215 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-mmx6-xv2h-w7x8.