What’s Vulnerable › Vulnerabilities

CVE-2019-16215

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2019-09-18 · updated 2026-06-17
• Weakness: CWE-1333

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.

Affected products

• zulip: before 2.0.5 — fixed in 2.0.5

How to fix

Upgrade to a fixed version: zulip 2.0.5. Check the vendor advisory for mitigations.

References

• https://blog.zulip.org/2019/09/11/zulip-server-2-0-5-security-release/
• https://github.com/zulip/zulip/commit/5797f013b3be450c146a4141514bda525f2f1b51
• https://blog.zulip.org/2019/09/11/zulip-server-2-0-5-security-release/
• https://github.com/zulip/zulip/commit/5797f013b3be450c146a4141514bda525f2f1b51

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