CVE Vulnerabilities

CVE-2019-16215

Inefficient Regular Expression Complexity

Published: Sep 18, 2019 | Modified: Feb 08, 2024
CVSS 3.x
6.5
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
4 MEDIUM
AV:N/AC:L/Au:S/C:N/I:N/A:P
RedHat/V2
RedHat/V3
Ubuntu

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

The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.

Affected Software

Name Vendor Start Version End Version
Zulip_server Zulip * 2.0.5 (excluding)

Extended Description

	  Attackers can create crafted inputs that
	  intentionally cause the regular expression to use
	  excessive backtracking in a way that causes the CPU
	  consumption to spike.

Potential Mitigations

References