Vulnerability Report

CVE-2018-20843

Title: Tenable Nessus XML External Entity (XXE)

XML External Entity (XXE)

Proof Of Concept

No public PoC currently indexed for CVE-2018-20843.

CWE Category CWE-611
Published Date Jun 24, 2019
Modified Date May 30, 2025
Exploit Status Not Found
Score 7.5 CVSS v3.1
Exploit Probability (EPSS)
5.58%

Vulnerability Summary

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).

Impacted Vendors

N
nessus 1
L
libexpat_project 1
T
tenable 1
N
novell 1
A
a1webserver 1
O
oracle 3

Reference Links

http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00039.html https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5226 https://github.com/libexpat/libexpat/blob/R_2_2_7/expat/Changes https://github.com/libexpat/libexpat/issues/186 https://github.com/libexpat/libexpat/pull/262 https://github.com/libexpat/libexpat/pull/262/commits/11f8838bf99ea0a6f0b76f9760c43704d00c4ff6 https://lists.debian.org/debian-lts-announce/2019/06/msg00028.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEJJSQSG3KSUQY4FPVHZ7ZTT7FORMFVD/ https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IDAUGEB3TUP6NEKJDBUBZX7N5OAUOOOK/ https://seclists.org/bugtraq/2019/Jun/39 https://security.gentoo.org/glsa/201911-08 https://security.netapp.com/advisory/ntap-20190703-0001/ https://support.f5.com/csp/article/K51011533 https://usn.ubuntu.com/4040-1/ https://usn.ubuntu.com/4040-2/ https://www.debian.org/security/2019/dsa-4472 https://www.oracle.com/security-alerts/cpuApr2021.html https://www.oracle.com/security-alerts/cpuapr2020.html https://www.oracle.com/security-alerts/cpuoct2020.html https://www.oracle.com/security-alerts/cpuoct2021.html https://www.tenable.com/security/tns-2021-11 http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00039.html https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5226 https://github.com/libexpat/libexpat/blob/R_2_2_7/expat/Changes https://github.com/libexpat/libexpat/issues/186 https://github.com/libexpat/libexpat/pull/262 https://github.com/libexpat/libexpat/pull/262/commits/11f8838bf99ea0a6f0b76f9760c43704d00c4ff6 https://lists.debian.org/debian-lts-announce/2019/06/msg00028.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEJJSQSG3KSUQY4FPVHZ7ZTT7FORMFVD/ https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IDAUGEB3TUP6NEKJDBUBZX7N5OAUOOOK/ https://seclists.org/bugtraq/2019/Jun/39 https://security.gentoo.org/glsa/201911-08 https://security.netapp.com/advisory/ntap-20190703-0001/ https://support.f5.com/csp/article/K51011533 https://usn.ubuntu.com/4040-1/ https://usn.ubuntu.com/4040-2/ https://www.debian.org/security/2019/dsa-4472 https://www.oracle.com/security-alerts/cpuApr2021.html https://www.oracle.com/security-alerts/cpuapr2020.html https://www.oracle.com/security-alerts/cpuoct2020.html https://www.oracle.com/security-alerts/cpuoct2021.html https://www.tenable.com/security/tns-2021-11
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v3.1
Source Entity 134c704f-9b21-4f2e-91b3-4a467353bcc0
Severity HIGH
7.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v2.0
Source Entity [email protected]
Severity HIGH
7.8
Access Vector
N/A
Authentication
N/A
RAW VECTOR AV:N/AC:L/Au:N/C:N/I:N/A:C

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2018-20843 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Stack

No specific products linked.