jQuery before 1.9.0 is vulnerable to Cross-site Scripting (XSS) attacks. The jQuery(strInput) function does not differentiate selectors from HTML in a reliable fashion. In vulnerable versions jQuery determined whether the input was HTML by looking for the '<' character anywhere in the string giving attackers more flexibility when attempting to construct a malicious payload. In fixed versions jQuery only deems the input to be HTML if it explicitly starts with the '<' character limiting exploitability only to attackers who can control the beginning of a string which is far less common.

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