01 Record

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

HighPUBLISHEDCNA: mitre

CNA base score7.5 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

View raw JSON

02 Description

03 Exploitation and scoring

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

7.10% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 94.1% of scored records. A rank, not a probability.

NVD base score

7.5 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD analysis status

Modified. NVD last modified this record on 2026-10-14.

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2019-06-24 16:06Z7 YR AGO

Last updated

2026-10-14 06:30Z15 DAYS AGO

Reserved

2019-06-24

Assigning CNA

mitre

Record state

PUBLISHED

Severity

High (CVSS 7.5)

CNA CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weaknesses

CWE-611Improper Restriction of XML External Entity ReferenceBase
CWE-400Uncontrolled Resource ConsumptionClass

Data version

5.2

Document digest

c177143b161e21996ffeb3d2bea0dfbec56624faa618157a19bef8453db62ba8

05 Affected products

VendorProductVersionsPlatforms

canonicalubuntu_linuxNot specified—

debiandebian_linuxNot specified—

fedoraprojectfedoraNot specified—

libexpat_projectlibexpatNot specified—

opensuseleapNot specified—

oraclehospitality_res_3700Not specified—

oraclehttp_serverNot specified—

oracleoutside_in_technologyNot specified—

redhatenterprise_linuxNot specified—

redhatjboss_core_servicesNot specified—

redhatjboss_enterprise_application_platformNot specified—

redhatjboss_enterprise_web_serverNot specified—

redhatopenshift_doNot specified—

redhatrhel_ausNot specified—

tenablenessusNot specified—

06 References

usn.ubuntu.comUSN-4040-1https://usn.ubuntu.com/4040-1/vendor-advisoryx_refsource_UBUNTU
usn.ubuntu.comUSN-4040-2https://usn.ubuntu.com/4040-2/vendor-advisoryx_refsource_UBUNTU
www.debian.orgDSA-4472https://www.debian.org/security/2019/dsa-4472vendor-advisoryx_refsource_DEBIAN
seclists.org20190628 [SECURITY] [DSA 4472-1] expat security updatehttps://seclists.org/bugtraq/2019/Jun/39mailing-listx_refsource_BUGTRAQ
lists.debian.org[debian-lts-announce] 20190629 [SECURITY] [DLA 1839-1] expat security updatehttps://lists.debian.org/debian-lts-announce/2019/06/msg00028.htmlmailing-listx_refsource_MLIST
lists.fedoraproject.orgFEDORA-2019-18868e1715https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEJJSQSG3KSUQY4FPVHZ7ZTT7FORMFVD/vendor-advisoryx_refsource_FEDORA
lists.fedoraproject.orgFEDORA-2019-139fcda84dhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IDAUGEB3TUP6NEKJDBUBZX7N5OAUOOOK/vendor-advisoryx_refsource_FEDORA
lists.opensuse.orgopenSUSE-SU-2019:1777http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00039.htmlvendor-advisoryx_refsource_SUSE
security.gentoo.orgGLSA-201911-08https://security.gentoo.org/glsa/201911-08vendor-advisoryx_refsource_GENTOO
www.oracle.comhttps://www.oracle.com/security-alerts/cpuapr2020.htmlx_refsource_MISC
www.oracle.comhttps://www.oracle.com/security-alerts/cpuoct2020.htmlx_refsource_MISC
github.comhttps://github.com/libexpat/libexpat/issues/186x_refsource_MISC
github.comhttps://github.com/libexpat/libexpat/pull/262x_refsource_MISC
github.comhttps://github.com/libexpat/libexpat/pull/262/commits/11f8838bf99ea0a6f0b76f9760c43704d00c4ff6x_refsource_MISC
github.comhttps://github.com/libexpat/libexpat/blob/R_2_2_7/expat/Changesx_refsource_MISC
bugs.chromium.orghttps://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5226x_refsource_MISC
security.netapp.comhttps://security.netapp.com/advisory/ntap-20190703-0001/x_refsource_CONFIRM
support.f5.comhttps://support.f5.com/csp/article/K51011533x_refsource_CONFIRM
www.oracle.comhttps://www.oracle.com/security-alerts/cpuApr2021.htmlx_refsource_MISC
www.oracle.comhttps://www.oracle.com/security-alerts/cpuoct2021.htmlx_refsource_MISC
www.tenable.comhttps://www.tenable.com/security/tns-2021-11x_refsource_CONFIRM
cert-portal.siemens.comhttps://cert-portal.siemens.com/productcert/html/ssa-398330.html

07 Fixed in

AlmaLinux 8

mingw32-expat
Fixed in 2.2.4-5.el8
mingw64-expat
Fixed in 2.2.4-5.el8

CloudLinux 8

mingw32-expat
Fixed in 2.2.4-5.el8
mingw64-expat
Fixed in 2.2.4-5.el8

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.

Debian 12

expat
Fixed in 2.2.6-2
libxmltok
No fix yet

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

expat
Fixed in 2.2.6-2

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

expat
Fixed in 2.2.6-2

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.