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Fencer Intel
medium 6.1

CVE-2018-19787 json

Improper Neutralization of Input During Web Page Generation in LXML

published 2018-12-02 7 y ago modified 2026-06-17 4 mo ago also GHSA-xp26-p53h-6h2p , PYSEC-2018-12 , EUVD-2018-0088

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

An issue was discovered in lxml before 4.2.5. lxml/html/clean.py in the lxml.html.clean module does not remove javascript: URLs that use escaping, allowing a remote attacker to conduct XSS attacks, as demonstrated by "j a v a s c r i p t:" in Internet Explorer. This is a similar issue to CVE-2014-3146.

Patch / fix

  • pypi lxml 4.2.5
  • lxml lxml 4.2.5
  • lxml Debian 14, Debian 13, Debian 12 4.2.5-1

debian advisories DEBIAN-CVE-2018-19787

  • lxml Ubuntu 14.04 LTS 3.3.3-1ubuntu0.2
  • lxml Ubuntu 16.04 LTS 3.5.0-1ubuntu0.1
  • lxml Ubuntu 18.04 LTS 4.2.1-1ubuntu0.1

ubuntu advisories UBUNTU-CVE-2018-19787

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • grafana OpenStack Cloud Crowbar 9, OpenStack Cloud 9 6.7.4-3.26.1
  • python-lxml OpenStack Cloud Crowbar 9, OpenStack Cloud 9 4.2.4-3.3.1
  • python-Pillow OpenStack Cloud Crowbar 9, OpenStack Cloud 9 5.2.0-3.17.1
  • ardana-barbican OpenStack Cloud 9 9.0+git.1644879908.8a641c1-3.13.1
  • rubygem-sinatra OpenStack Cloud Crowbar 9 1.4.6-4.3.1
  • openstack-cinder OpenStack Cloud Crowbar 9, OpenStack Cloud 9 13.0.10~dev24-3.34.2
  • openstack-ironic OpenStack Cloud Crowbar 9, OpenStack Cloud 9 11.1.5~dev18-3.28.2
  • openstack-neutron OpenStack Cloud Crowbar 9, OpenStack Cloud 9 13.0.8~dev206-3.40.1

suse advisories SUSE-SU-2022:1729-1SUSE-SU-2022:0895-1SUSE-SU-2022:0803-1

  • python-lxml openSUSE Leap 15.3 4.7.1-3.7.1

opensuse advisories openSUSE-SU-2022:0803-1

  • python-lxml CBL-Mariner 2.0 4.8.0-1

azure linux advisories AZL-6806

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-19787 updated cvss 4.7

python-lxml: XSS in lxml.html.clean module in lxml/html/clean.py

  • Red Hat Enterprise Linux 5 python-lxml Red Hat Enterprise Linux 6 python-lxml Red Hat Enterprise Linux 7 python-lxml Red Hat Enterprise Linux 8 python-lxml, python3-lxml Red Hat Enterprise Linux OpenStack Platform 7 (Kilo) python-lxml Red Hat OpenStack Platform 8 (Liberty) python-lxml
    +4 more products
    Red Hat OpenStack Platform 9 (Mitaka) python-lxml Red Hat OpenStack Platform 10 (Newton) python-lxml Red Hat OpenStack Platform 12 (Pike) python-lxml Red Hat OpenStack Platform 13 (Queens) python-lxml
    affected: no fix planned “Will not fix”
  • Red Hat OpenStack Platform 14 (Rocky) python-lxml
    affected: no fix available

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
10 mo ago

Exploit prediction

2.44% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CNA 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 3.0 6.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N
GitHub 3.0 6.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
pypi lxml
<4.2.5
4.2.5

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.