If an XPath expression is built using string concatenation, and the components of the concatenation include user input, it makes it very easy for a user to create a malicious XPath expression.

If user input must be included in an XPath expression, either sanitize the data or use variable references to safely embed it without altering the structure of the expression.

In this example, the code accepts a user name specified by the user, and uses this unvalidated and unsanitized value in an XPath expression constructed using the xpath package. This is vulnerable to the user providing special characters or string sequences that change the meaning of the XPath expression to search for different values.

Instead, embed the user input using the variable replacement mechanism offered by xpath:

  • OWASP: Testing for XPath Injection.
  • OWASP: XPath Injection.
  • npm: xpath.
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