FlawAtlas
Search the atlas
CVE-2021-43818 High

CVE-2021-43818

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.

Exploit probability 2.5%
Published December 13, 2021
Required by Not available
Last source change April 9, 2026

02 / AFFECTED SOFTWARE

Affected packages

PyPI lxml

97 explicit affected versions

Unknown Unknown

90 explicit affected versions

PyPI lxml

148 explicit affected versions

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities GHSA-55x5-fj6c-h6m8

### Impact 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. ### Patches The issue has been resolved in lxml 4.6.5. ### Workarounds None. ### References The issues are tracked under the report IDs GHSL-2021-1037 and GHSL-2021-1038.

View original source
Open Source Vulnerabilities CVE-2021-43818

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.

View original source
Open Source Vulnerabilities PYSEC-2021-852

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.

View original source

05 / REFERENCES

Further evidence