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TI-2018-14806 Aliases CVE-2018-20843GHSA-hj5j-c8qp-mgmv

In libexpat in Expat before 2.2.7, XML input including XML names that contain a large…

Priority MEDIUM 49CWE-611Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 15 fixed, 4 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-611 and the CVSS impact.

Summary

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).

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.07107 94th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial Red Hat: 7 advisoriesRed Hat: 15 fixed, 4 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 19

CPEVersionsRoleVendor
cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*before 2.2.7Vulnerablelibexpat project
cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:-:*:*:*12.04VulnerableCanonical
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*14.04VulnerableCanonical
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*16.04VulnerableCanonical
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*18.04VulnerableCanonical
cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:*18.10VulnerableCanonical
cpe:2.3:o:canonical:ubuntu_linux:19.04:*:*:*:*:*:*:*19.04VulnerableCanonical
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*8.0VulnerableDebian
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*9.0VulnerableDebian
cpe:2.3:o:fedoraproject:fedora:29:*:*:*:*:*:*:*29VulnerableFedoraproject
  • cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:* Versions before 2.2.7 Vulnerable ·libexpat project
  • cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:-:*:*:* Versions 12.04 Vulnerable ·Canonical
  • cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:* Versions 14.04 Vulnerable ·Canonical
  • cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* Versions 16.04 Vulnerable ·Canonical
  • cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* Versions 18.04 Vulnerable ·Canonical
  • cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:* Versions 18.10 Vulnerable ·Canonical
  • cpe:2.3:o:canonical:ubuntu_linux:19.04:*:*:*:*:*:*:* Versions 19.04 Vulnerable ·Canonical
  • cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Debian
  • cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
  • cpe:2.3:o:fedoraproject:fedora:29:*:*:*:*:*:*:* Versions 29 Vulnerable ·Fedoraproject
Show 9 more CPE
CPEVersionsRoleVendor
cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*30VulnerableFedoraproject
cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:*15.0VulnerableopenSUSE
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*15.1VulnerableopenSUSE
cpe:2.3:a:oracle:hospitality_res_3700:*:*:*:*:*:*:*:*5.7 – 5.7.6VulnerableOracle
cpe:2.3:a:oracle:http_server:12.1.3.0:*:*:*:*:*:*:*12.1.3.0VulnerableOracle
cpe:2.3:a:oracle:http_server:12.2.1.4.0:*:*:*:*:*:*:*12.2.1.4.0VulnerableOracle
cpe:2.3:a:oracle:outside_in_technology:8.5.4:*:*:*:*:*:*:*8.5.4VulnerableOracle
cpe:2.3:a:oracle:outside_in_technology:8.5.5:*:*:*:*:*:*:*8.5.5VulnerableOracle
cpe:2.3:a:tenable:nessus:*:*:*:*:*:*:*:*before 8.15.0VulnerableTenable
  • cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:* Versions 30 Vulnerable ·Fedoraproject
  • cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:* Versions 15.0 Vulnerable ·openSUSE
  • cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:* Versions 15.1 Vulnerable ·openSUSE
  • cpe:2.3:a:oracle:hospitality_res_3700:*:*:*:*:*:*:*:* Versions 5.7 – 5.7.6 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:http_server:12.1.3.0:*:*:*:*:*:*:* Versions 12.1.3.0 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:http_server:12.2.1.4.0:*:*:*:*:*:*:* Versions 12.2.1.4.0 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:outside_in_technology:8.5.4:*:*:*:*:*:*:* Versions 8.5.4 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:outside_in_technology:8.5.5:*:*:*:*:*:*:* Versions 8.5.5 Vulnerable ·Oracle
  • cpe:2.3:a:tenable:nessus:*:*:*:*:*:*:*:* Versions before 8.15.0 Vulnerable ·Tenable

Remediation

Red Hat 7 advisories

  • RHSA-2025:22871 Released 2025-12-09 · Red Hat rating Important
    expat security update
    • Red Hat Enterprise Linux BaseOS AUS (v. 8.2) expat-2.2.10-1.el8_2
  • RHSA-2021:0949 Released 2021-03-22 · Red Hat rating Low
    Red Hat OpenShift Do openshift/odo-init-image 1.1.3 security update
    • OpenShift Do 1 openshiftdo/odo-init-image-rhel7
  • RHSA-2020:4484 Released 2020-11-04 · Red Hat rating Moderate
    expat security update
    • Red Hat Enterprise Linux BaseOS (v. 8) expat-2.2.5-4.el8, expat-devel-2.2.5-4.el8
Show 4 more Red Hat advisories
  • RHSA-2020:4846 Released 2020-11-04 · Red Hat rating Moderate
    mingw-expat security update
    • Red Hat CodeReady Linux Builder (v. 8) mingw-expat-2.2.4-5.el8, mingw32-expat-2.2.4-5.el8, mingw64-expat-2.2.4-5.el8
  • RHSA-2020:3952 Released 2020-09-29 · Red Hat rating Moderate
    expat security update
    • Red Hat Enterprise Linux Client (v. 7) expat-2.1.0-12.el7
    • Red Hat Enterprise Linux Client Optional (v. 7) expat-devel-2.1.0-12.el7, expat-static-2.1.0-12.el7
    • Red Hat Enterprise Linux ComputeNode (v. 7) expat-2.1.0-12.el7
    • Red Hat Enterprise Linux ComputeNode Optional (v. 7) expat-devel-2.1.0-12.el7, expat-static-2.1.0-12.el7
    • Red Hat Enterprise Linux Server (v. 7) expat-2.1.0-12.el7, expat-2.1.0-12.el7.ppc, expat-devel-2.1.0-12.el7 +1
    • Red Hat Enterprise Linux Server Optional (v. 7) expat-static-2.1.0-12.el7, expat-static-2.1.0-12.el7.ppc
    • Red Hat Enterprise Linux Workstation (v. 7) expat-2.1.0-12.el7, expat-devel-2.1.0-12.el7
    • Red Hat Enterprise Linux Workstation Optional (v. 7) expat-static-2.1.0-12.el7
  • RHSA-2020:2646 Released 2020-06-22 · Red Hat rating Important
    Red Hat JBoss Core Services Apache HTTP Server 2.4.37 SP3 security update
    • Red Hat JBoss Core Services
  • RHSA-2020:2644 Released 2020-06-22 · Red Hat rating Important
    Red Hat JBoss Core Services Apache HTTP Server 2.4.37 SP3 security update
    • Red Hat JBoss Core Services on RHEL 6 Server jbcs-httpd24-curl-7.64.1-36.jbcs.el6, jbcs-httpd24-httpd-2.4.37-57.jbcs.el6, jbcs-httpd24-httpd-devel-2.4.37-57.jbcs.el6 +18
    • Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-curl-7.64.1-36.jbcs.el7, jbcs-httpd24-httpd-2.4.37-57.jbcs.el7, jbcs-httpd24-httpd-devel-2.4.37-57.jbcs.el7 +19

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 5AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat JBoss Enterprise Application Platform 6AffectedNo fix planned: Out of support scope
Red Hat JBoss Enterprise Web Server 2AffectedNo fix planned: Out of support scope
OpenShift Do 1Fixed RHSA-2021:0949
Red Hat CodeReady Linux Builder (v. 8)Fixed RHSA-2020:4846
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2020:4484
Red Hat Enterprise Linux BaseOS AUS (v. 8.2)Fixed RHSA-2025:22871
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2020:3952
Red Hat Enterprise Linux Client Optional (v. 7)Fixed RHSA-2020:3952
Red Hat Enterprise Linux ComputeNode (v. 7)Fixed RHSA-2020:3952
Red Hat Enterprise Linux ComputeNode Optional (v. 7)Fixed RHSA-2020:3952
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2020:3952
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2020:3952
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2020:3952
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2020:3952
Red Hat JBoss Core ServicesFixed RHSA-2020:2646
Red Hat JBoss Core Services on RHEL 6 ServerFixed RHSA-2020:2644
Red Hat JBoss Core Services on RHEL 7 ServerFixed RHSA-2020:2644
Not affected: 4 products
  • Red Hat Enterprise Linux 5
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux BaseOS AUS (v. 8.2)

Timeline

  1. 2026-10-02 Threatist record created from CVE-2018-20843
  2. 2026-10-03 Alias added: GHSA-hj5j-c8qp-mgmv

References

Exploit 1

Patch 6

Advisory 14

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences