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)
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.071 (94.0th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 94th percentile — 94.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.071 · newest: 0.071 · change: 0.000
Affected products
- Libexpat Project
- Oracle Hospitality Res 3700
- Oracle HTTP Server — versions 12.1.3.0, 12.2.1.4.0
- Oracle Outside In Technology — versions 8.5.4, 8.5.5
- Tenable Nessus
- Canonical Ubuntu Linux — versions 12.04, 14.04, 16.04
- Debian Linux — versions 8.0, 9.0
- Fedoraproject Fedora — versions 29, 30
- openSUSE Leap — versions 15.0, 15.1
Weakness classification (CWE)
Public proof-of-concept exploits
References
- usn.ubuntu.com/4040-1/ (vendor-advisory, Third Party Advisory)
- usn.ubuntu.com/4040-2/ (vendor-advisory, Third Party Advisory)
- www.debian.org/security/2019/dsa-4472 (vendor-advisory, Third Party Advisory)
- seclists.org/bugtraq/2019/Jun/39 (mailing-list, Mailing List, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2019/06/msg00028.html (mailing-list, Mailing List, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.opensuse.org/opensuse-security-announce/2019-07/msg00039.html (vendor-advisory, Mailing List, Third Party Advisory)
- security.gentoo.org/glsa/201911-08 (vendor-advisory, Third Party Advisory)
- www.oracle.com/security-alerts/cpuapr2020.html (Patch, Third Party Advisory)
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.