Is CVE-2018-20843 actively exploited?

CVE-2018-20843 has no public evidence of in-the-wild exploitation as of 2025-05-30.

What is the CVSS score for CVE-2018-20843?

CVE-2018-20843 has a CVSS score of 7.5 (HIGH severity). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

How do I patch CVE-2018-20843?

Patch guidance is available from libexpat project security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2018-20843.

Fix CVE-2018-20843 - HIGH libexpat project libexpat

Q: Which products are affected by CVE-2018-20843?

19 products: libexpat project libexpat, canonical ubuntu linux, canonical ubuntu linux, canonical ubuntu linux, canonical ubuntu linux, and 14 more.

Description

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).

CVSS Metrics

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector: network
Complexity: low
Privileges: none
User Action: none
Scope: unchanged
Confidentiality: none
Integrity: none
Availability: high
Weaknesses: CWE-611 · XML External Entity (XXE)CWE-611 · XML External Entity (XXE)

Metadata

Primary Vendor: LIBEXPAT_PROJECT
Published: 6/24/2019
Last Modified: 5/30/2025
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

Affected Products

libexpat_project : libexpatcanonical : ubuntu_linuxcanonical : ubuntu_linuxcanonical : ubuntu_linuxcanonical : ubuntu_linuxcanonical : ubuntu_linuxcanonical : ubuntu_linuxdebian : debian_linuxdebian : debian_linuxfedoraproject : fedorafedoraproject : fedoraopensuse : leapopensuse : leaporacle : hospitality_res_3700oracle : http_serveroracle : http_serveroracle : outside_in_technologyoracle : outside_in_technologytenable : nessus

Remediation Guidance

Executive Summary

Cite this page

CVE-2018-20843. CVEDatabase.com. Retrieved 1 May 2026. https://cvedatabase.com/cve/CVE-2018-20843

View on NIST NVD

CVE-2018-20843 vulnerability