CVE-2018-20843: XEE

Published Jun 24, 2019
·
Updated

In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).

Other sources

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.

libexpat is vulnerable to a denial of service, caused by an error in the XML parser. By persuading a victim to open a specially-crafted file, a remote attacker could exploit this vulnerability to consume all available CPU resources.

IBM

Affected Software

37 affected componentsFixes available
redhat/jbcs-httpd24-curl<0:7.64.1-36.jbcs.el6
0:7.64.1-36.jbcs.el6
redhat/jbcs-httpd24-httpd<0:2.4.37-57.jbcs.el6
0:2.4.37-57.jbcs.el6
redhat/jbcs-httpd24-nghttp2<0:1.39.2-25.jbcs.el6
0:1.39.2-25.jbcs.el6
redhat/jbcs-httpd24-curl<0:7.64.1-36.jbcs.el7
0:7.64.1-36.jbcs.el7
redhat/jbcs-httpd24-httpd<0:2.4.37-57.jbcs.el7
0:2.4.37-57.jbcs.el7
redhat/jbcs-httpd24-nghttp2<0:1.39.2-25.jbcs.el7
0:1.39.2-25.jbcs.el7
redhat/jbcs-httpd24-openssl-pkcs11<0:0.4.10-7.jbcs.el7
0:0.4.10-7.jbcs.el7
redhat/expat<0:2.1.0-12.el7
0:2.1.0-12.el7
redhat/mingw-expat<0:2.2.4-5.el8
0:2.2.4-5.el8
redhat/expat<0:2.2.5-4.el8
0:2.2.5-4.el8
debian/expat<=2.2.6-1, <=2.2.0-2+deb9u1, <=2.2.0-1
2.2.6-22.2.0-2+deb9u2
IBM RDNG<=6.0.2
IBM RDNG<=6.0.6.1
IBM RDNG<=6.0.6
IBM DOORS Next<=7.0
Libexpat Project Libexpat<2.2.7
Canonical Ubuntu Linux=12.04
Canonical Ubuntu Linux=14.04
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=18.04
Canonical Ubuntu Linux=18.10
Canonical Ubuntu Linux=19.04
Debian Debian Linux=8.0
Debian Debian Linux=9.0
Fedoraproject Fedora=29
Fedoraproject Fedora=30
openSUSE Leap=15.0
openSUSE Leap=15.1
Oracle Hospitality RES 3700>=5.7<=5.7.6
Oracle HTTP Server=12.1.3.0
Oracle HTTP Server=12.2.1.4.0
Oracle Outside In Technology=8.5.4
Oracle Outside In Technology=8.5.5
Tenable Nessus<8.15.0
redhat/expat<2.2.7
2.2.7
debian/expat
2.2.10-2+deb11u52.2.10-2+deb11u72.5.0-1+deb12u22.5.0-1+deb12u12.7.1-22.7.3-2
debian/libxmltok<=1.2-4

Event History

Jun 24, 2019
CVE Published
12:00 AM
CVE Published
via MITRE·04:06 PM
Data Sourced
via MITRE·04:06 PM
Description
Jun 25, 2019
Data Sourced
via Red Hat·08:58 AM
DescriptionSeverityAffected Software
Jan 11, 2024
Data Sourced
via Launchpad·11:00 PM
Description
Jan 18, 2025
Data Sourced
via Ubuntu·02:25 AM
RemedyDescriptionSeverityAffected Software
Jan 26, 2026
Data Sourced
via Debian·10:44 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is the severity of CVE-2018-20843?

CVE-2018-20843 has been classified as a high-severity vulnerability due to its potential to cause denial-of-service attacks by consuming excessive resources.

2

How do I fix CVE-2018-20843?

To fix CVE-2018-20843, update your libexpat version to 2.2.7 or later as recommended by your software provider.

3

What software is affected by CVE-2018-20843?

CVE-2018-20843 affects several versions of libexpat, particularly versions prior to 2.2.7, along with specific Red Hat packages like jbcs-httpd24-curl and jbcs-httpd24-httpd.

4

What are the symptoms of CVE-2018-20843 exploitation?

Exploitation of CVE-2018-20843 may result in the XML parser consuming high amounts of RAM and CPU resources, leading to performance degradation or application crashes.

5

Is CVE-2018-20843 present in my system?

To determine if CVE-2018-20843 is present in your system, check the version of the libexpat library and any affected software packages installed.

Contact

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