XXE in Libexpat Project

CVE-2018-20843

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).

Vulnerability class: XXE (XML External Entity)

EPSS: 0.071 (93.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

  • cve@mitre.org (x_refsource_UBUNTU, vendor-advisory, Third Party Advisory)
  • cve@mitre.org (x_refsource_UBUNTU, vendor-advisory, Third Party Advisory)
  • cve@mitre.org (vendor-advisory, Third Party Advisory, x_refsource_DEBIAN)
  • cve@mitre.org (mailing-list, x_refsource_BUGTRAQ, Mailing List, Third Party Advisory)
  • cve@mitre.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
  • cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
  • cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
  • cve@mitre.org (vendor-advisory, Mailing List, Third Party Advisory, x_refsource_SUSE)
  • cve@mitre.org (vendor-advisory, Third Party Advisory, x_refsource_GENTOO)
  • cve@mitre.org (Patch, Third Party Advisory, x_refsource_MISC)

Frequently asked questions

What is CVE-2018-20843?
CVE-2018-20843 is a high-severity vulnerability in Libexpat Project, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 7.5/10. Published 2019-06-24.
How severe is CVE-2018-20843?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2018-20843 known to be exploited?
5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.