CVE-2021-28957

Related Vulnerabilities: CVE-2021-28957  

A flaw was found in python-lxml. The HTML5 formaction attribute is not input sanitized like the HTML action attribute is which can lead to a Cross-Site Scripting attack (XSS) when an application uses python-lxml to sanitize user inputs. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Description

A flaw was found in python-lxml. The HTML5 formaction attribute is not input sanitized like the HTML action attribute is which can lead to a Cross-Site Scripting attack (XSS) when an application uses python-lxml to sanitize user inputs. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Statement

Web applications vulnerable to this flaw, where a XSS attack can be accomplished, are only those that use python-lxml to sanitize HTML input and that allow user data to be placed in the "formaction" attribute of a form button.

Web applications vulnerable to this flaw, where a XSS attack can be accomplished, are only those that use python-lxml to sanitize HTML input and that allow user data to be placed in the "formaction" attribute of a form button.

Additional Information

  • Bugzilla 1941534: CVE-2021-28957 python-lxml: missing input sanitization for formaction HTML5 attributes may lead to XSS
  • CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
  • FAQ: Frequently asked questions about CVE-2021-28957