CVE-2021-43818CWE-74CWE-79

HTML Cleaner allows crafted and SVG embedded scripts to pass through

High · published December 13, 2021

CVSS v3.1
8.2
EPSS
3%
Percentile
85.6
In the wild
Unconfirmed
What it is

lxml is a library for processing XML and HTML in the Python language. Prior to version 4.6.5, the HTML Cleaner in lxml.html lets certain crafted script content pass through, as well as script content in SVG files embedded using data URIs. Users that employ the HTML cleaner in a security relevant context should upgrade to lxml 4.6.5 to receive a patch. There are no known workarounds available.

The record
Technical detail
CVSS v3.1
8.2 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.02663 · 85.6th percentile
Weaknesses
CWE-74 · Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection'); CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2021-12-13T18:05Z
EPSS history
Timeline
  • 13 DEC 18:05Z
    HTML Cleaner allows crafted and SVG embedded scripts to pass through
    cvelistv5