Vulnerabilities > CVE-2020-5227 - XML Entity Expansion vulnerability in Feedgen Project Feedgen

047910
CVSS 7.5 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
HIGH
network
low complexity
feedgen-project
CWE-776
nessus
NVD
Published: 2020-01-28
Updated: 2023-11-07

Summary

Feedgen (python feedgen) before 0.9.0 is susceptible to XML Denial of Service attacks. The *feedgen* library allows supplying XML as content for some of the available fields. This XML will be parsed and integrated into the existing XML tree. During this process, feedgen is vulnerable to XML Denial of Service Attacks (e.g. XML Bomb). This becomes a concern in particular if feedgen is used to include content from untrused sources and if XML (including XHTML) is directly included instead of providing plain tex content only. This problem has been fixed in feedgen 0.9.0 which disallows XML entity expansion and external resources.

Vulnerable Configurations

Part Description Count
Application
Feedgen_Project
22

Common Weakness Enumeration (CWE)

Nessus

NASL familyFedora Local Security Checks
NASL idFEDORA_2020-8493201E90.NASL
descriptionNew upstream version 0.9.0 (fixes CVE-2020-5227) Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
last seen2020-06-01
modified2020-06-02
plugin id133577
published2020-02-10
reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/133577
titleFedora 31 : python-feedgen (2020-8493201e90)
code
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Fedora Security Advisory FEDORA-2020-8493201e90.
#

include("compat.inc");

if (description)
{
  script_id(133577);
  script_version("1.2");
  script_cvs_date("Date: 2020/02/12");

  script_cve_id("CVE-2020-5227");
  script_xref(name:"FEDORA", value:"2020-8493201e90");

  script_name(english:"Fedora 31 : python-feedgen (2020-8493201e90)");
  script_summary(english:"Checks rpm output for the updated package.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Fedora host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"New upstream version 0.9.0 (fixes CVE-2020-5227)

Note that Tenable Network Security has extracted the preceding
description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as
possible without introducing additional issues."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bodhi.fedoraproject.org/updates/FEDORA-2020-8493201e90"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected python-feedgen package."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:python-feedgen");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:31");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/01/28");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/02/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/02/10");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Fedora Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("rpm.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/RedHat/release");
if (isnull(release) || "Fedora" >!< release) audit(AUDIT_OS_NOT, "Fedora");
os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
os_ver = os_ver[1];
if (! preg(pattern:"^31([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 31", "Fedora " + os_ver);

if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);


cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu);


flag = 0;
if (rpm_check(release:"FC31", reference:"python-feedgen-0.9.0-1.fc31")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "python-feedgen");
}

References