CVE-2021-28957: PYSEC-2021-19 - An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3. When disabling the safe_attrs_only and forms argume

CVE-2021-28957 · Severity: low · CVSS 3.1 · Published 2021-03-21

Vendors: PyPI.

Executive brief

An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.

Affected products

PyPI lxml

Related threats

lxml XXE in iterparse and ETCompatXMLParser
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