CVE-2018-20843
expat: large number of colons in input makes parser consume high amount of resources, leading to DoS
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · June 24, 2019
Updated · September 21, 2026
Description
It was discovered that the "setElementTypePrefix()" function incorrectly extracted XML namespace prefixes. By tricking an application into processing a specially crafted XML file, an attacker could cause unusually high consumption of memory resources and possibly lead to a denial of service.
Statement
When processing a specially crafted XML file, expat may use more memory than ultimately necessary, which can also lead to increased CPU usage and longer processing times. Depending on available system resources and configuration, this may also lead to the application triggering the Out-Of-Memory-Killer, causing the application to be terminated.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE-400 · Uncontrolled Resource Consumption