CVE-2018-20843: canonical ubuntu_linux

Modified

AliasesALPINE-CVE-2018-20843MGASA-2019-0274SUSE-SU-2019:1834-1+9 more

Published 24-06-2019Last modified 14-10-2026

Vulnerability summary

CVE-2018-20843 is a high (CVSS 7.8) vulnerability in canonical ubuntu_linux. EPSS estimates a 7.11% chance of exploitation in the next 30 days, higher than 94.2% of scored vulnerabilities. 1 public exploit is recorded.

Priority

Prioritisepublic exploit

Public exploit (GitHub, Date unknown)

Source freshness unavailable

How is this decided?

CVSS score

7.8/10

010

High · v2.0 (NVD)

EPSS score

7.11%

0%100%

Low · 0.00 pp in 30 days

KEVNot listedNot listed by any tracked catalog.

RansomwareNot flaggedNo ransomware use recorded.

Public exploits1github

Advisory lineage

Upstream 0 · Downstream 8 · Related 4

OPENSUSE-SU-2024:10748-1 RHSA-2020:2644 RHSA-2020:3952 RHSA-2020:4484 RHSA-2025:22871 USN-4852-1+2 more

Timeline

24-06-2019
PublishedVulnerability first disclosed.
14-10-2026
Last modifiedVulnerability information updated.

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

7 scores · 6 sources · 2 versions

v3.17.5v2.07.8

EPSS trend

Probability

7.11%

Chance of exploitation in the next 30 days

Percentile

94%

Versus all other CVEs

30-day change

No change 0.00 pp

From 7.11% on 05-10-2026

05-10-202604-11-2026

Known exploited

Compare KEV catalogs

CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found

githubUnverified
Libexpat
Maturity: poc

Weaknesses

CWE · root cause

CWE-611Improper Restriction of XML External Entity ReferenceThe product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu14 products

ayttmAll versions (No fix recorded)
cableswigAll versions (No fix recorded)
cadaverAll versions (No fix recorded)
coin3All versions (No fix recorded)
expat< 2.1.0-4ubuntu1.4+esm1 | < 2.1.0-7ubuntu0.16.04.4 | < 2.2.5-3ubuntu0.1

Show all 14

Suse6 products

expat&distro=SUSE Linux Enterprise Desktop 12 SP4< 2.1.0-21.6.1
expat&distro=SUSE Linux Enterprise Module for Basesystem 15< 2.2.5-3.3.1
expat&distro=SUSE Linux Enterprise Module for Basesystem 15 SP1< 2.2.5-3.3.1
expat&distro=SUSE Linux Enterprise Server 12 SP4< 2.1.0-21.6.1
expat&distro=SUSE Linux Enterprise Server for SAP Applications 12 SP4< 2.1.0-21.6.1

Show all 6

Redhat5 products

mingw-expat< 0:2.2.4-5.el8
mingw32-expat< 0:2.2.4-5.el8
mingw32-expat-debuginfo< 0:2.2.4-5.el8
mingw64-expat< 0:2.2.4-5.el8
mingw64-expat-debuginfo< 0:2.2.4-5.el8

Debian3 products

expat< 2.2.0-2+deb9u2 | < 2.1.0-6+deb8u5 | < 2.2.6-2
libxmltokAll versions (No fix recorded)
debian_linuxEOL8.0 | 9.0

Opensuse3 products

leapEOL15.0 | 15.1
expat&distro=openSUSE Leap 15.0< 2.2.5-lp151.3.3.1
expat&distro=openSUSE Leap 15.1< 2.2.5-lp151.3.3.1

Oracle3 products

hospitality_res_3700≥ 5.7, ≤ 5.7.6
http_server12.1.3.0 | 12.2.1.4.0
outside_in_technology8.5.4 | 8.5.5

Mageia2 products

expat< 2.2.7-1.mga6
expat< 2.2.7-1.mga7

Alpine1 product

expat< 2.2.7-r0

Canonical1 product

ubuntu_linuxEOL12.04 | 14.04 | 16.04 | 18.04 | 18.10 | 19.04

Fedoraproject1 product

fedoraEOL29 | 30

Libexpat_project1 product

libexpat< 2.2.7

Tenable1 product

nessus< 8.15.0

12 vendors · 41 products

References

46 links

usn.ubuntu.com/4040-1/Vendor AdvisoryX Refsource UBUNTUThird Party Advisory
usn.ubuntu.com/4040-2/Vendor AdvisoryX Refsource UBUNTUThird Party Advisory
www.debian.org/security/2019/dsa-4472Vendor AdvisoryX Refsource DEBIANThird Party AdvisoryWEB
seclists.org/bugtraq/2019/Jun/39Mailing ListX Refsource BUGTRAQThird Party Advisory
lists.debian.org/debian-lts-announce/2019/06/msg00028.htmlMailing ListX Refsource MLISTThird Party Advisory
lists.fedoraproject.org/archives/…Vendor AdvisoryX Refsource FEDORA
lists.fedoraproject.org/archives/…Vendor AdvisoryX Refsource FEDORA
lists.opensuse.org/opensuse-security-announce/2019-07/msg00039.htmlVendor AdvisoryX Refsource SUSEMailing ListThird Party Advisory
security.gentoo.org/glsa/201911-08Vendor AdvisoryX Refsource GENTOOThird Party Advisory
www.oracle.com/security-alerts/cpuapr2020.htmlX Refsource MISCPatchThird Party Advisory

Show all 46 references

www.oracle.com/security-alerts/cpuoct2020.htmlX Refsource MISCPatchThird Party Advisory
github.com/libexpat/libexpat/issues/186X Refsource MISCIssue TrackingPatchThird Party Advisory
github.com/libexpat/libexpat/pull/262X Refsource MISCExploitPatchThird Party AdvisoryREPORT
github.com/libexpat/libexpat/pull/262/commits/11f8838bf99ea0a6f0b76f9760c43704d00c4ff6X Refsource MISCPatchThird Party AdvisoryREPORT
github.com/libexpat/libexpat/blob/R_2_2_7/expat/ChangesX Refsource MISCRelease NotesThird Party AdvisoryWEBREPORT
bugs.chromium.org/p/oss-fuzz/issues/detail?id=5226X Refsource MISCIssue TrackingThird Party AdvisoryREPORT
security.netapp.com/advisory/ntap-20190703-0001/X Refsource CONFIRMThird Party Advisory
support.f5.com/csp/article/K51011533X Refsource CONFIRMThird Party Advisory
www.oracle.com/security-alerts/cpuApr2021.htmlX Refsource MISCPatchThird Party Advisory
www.oracle.com/security-alerts/cpuoct2021.htmlX Refsource MISCPatchThird Party Advisory
www.tenable.com/security/tns-2021-11X Refsource CONFIRMThird Party Advisory
security.alpinelinux.org/vuln/CVE-2018-20843Advisory
advisories.mageia.org/MGASA-2019-0274.htmlAdvisory
bugs.mageia.org/show_bug.cgi?id=25019REPORT
www.suse.com/support/update/announcement/2019/suse-su-20191834-1/Advisory
bugzilla.suse.com/1139937REPORT
www.suse.com/security/cve/CVE-2018-20843WEB
www.suse.com/support/update/announcement/2019/suse-su-20191835-1/Advisory
access.redhat.com/errata/RHSA-2020:4846Advisory
access.redhat.com/security/updates/classification/ARTICLE
access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/8.3_release_notes/ARTICLE
bugzilla.redhat.com/show_bug.cgi?id=1723723REPORT
security.access.redhat.com/data/csaf/v2/advisories/2020/rhsa-2020_4846.jsonAdvisory
access.redhat.com/security/cve/CVE-2018-20843REPORT
www.cve.org/CVERecord?id=CVE-2018-20843AdvisoryREPORT
nvd.nist.gov/vuln/detail/CVE-2018-20843AdvisoryOval
bugs.debian.org/cgi-bin/bugreport.cgi?bug=931031ARTICLE
ubuntu.com/security/CVE-2018-20843REPORT
ubuntu.com/security/notices/USN-4040-1Advisory
ubuntu.com/security/notices/USN-4040-2Advisory
ubuntu.com/security/notices/USN-5455-1Advisory
ubuntu.com/security/notices/USN-4852-1Advisory
ubuntu.com/security/notices/USN-7199-1Advisory
security-tracker.debian.org/tracker/CVE-2018-20843Advisory
lists.opensuse.org/archives/…Advisory
cert-portal.siemens.com/productcert/html/ssa-398330.html