CVE-2019-16215: Zulip Server

Medium severity, CVSS 6.5. EPSS: 1.2% chance of exploitation in the next 30 days.

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.

Affected products

• Zulip Zulip Server: before 2.0.5 (fixed in 2.0.5)

Published 2019-09-18. Last modified 2026-06-17.