CVE-2018-19787

Name: CVE-2018-19787
Creator: NVD / NIST
Published: 2018-12-02T10:29:00.227+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 2.44%

Last modified Jun 17, 2026

CVE-2018-19787 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. 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. EPSS estimates a 2.44% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

6.1/10

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

EPSS Probability

2.44%

82.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Lxml	Lxml	< 4.2.5
Debian	Debian Linux	8.0
Canonical	Ubuntu Linux	12.04
Canonical	Ubuntu Linux	14.04
Canonical	Ubuntu Linux	16.04
Canonical	Ubuntu Linux	18.04

References

https://github.com/lxml/lxml/commit/6be1d081b49c97cfd7b3fbd934a193b668629109Patch, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2018/12/msg00001.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/11/msg00044.html
https://usn.ubuntu.com/3841-1/Third Party Advisory
https://usn.ubuntu.com/3841-2/Third Party Advisory
https://github.com/lxml/lxml/commit/6be1d081b49c97cfd7b3fbd934a193b668629109Patch, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2018/12/msg00001.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/11/msg00044.html
https://usn.ubuntu.com/3841-1/Third Party Advisory
https://usn.ubuntu.com/3841-2/Third Party Advisory

Timeline

Published: Dec 2, 2018
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2018-19787?

How severe is CVE-2018-19787?

CVE-2018-19787 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 2.44% probability of exploitation in the next 30 days.

How do I fix CVE-2018-19787?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2018-19787?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST