CVE-2020-11022 identifies a critical JavaScript vulnerability in jQuery's htmlPrefilter method that enables cross-site scripting attacks through DOM manipulation functions. This vulnerability affects jQuery versions 1.2.0 through 3.4.1, with a CVSS score of 6.1 (Medium severity), discovered in April 2020. The vulnerability details reveal that HTML content from untrusted sources can execute malicious code when processed through jQuery's .html(), .append(), and related DOM manipulation methods, even after sanitization. The jQuery htmlPrefilter method, designed to ensure XHTML-compliant closing tags, contains edge cases in its HTML parser that create unintended consequences and substantial exploit risk for web applications. The technical root cause lies in jQuery's HTML parsing logic, where specific input patterns can bypass standard sanitization procedures and achieve remote code execution. Known exploited vulnerabilities of this type have prompted security advisories from major organizations including Oracle, Debian, and Drupal, highlighting the widespread impact across multiple package ecosystems including npm, NuGet, Maven, RubyGems, and Composer. Mitigation steps include upgrading to jQuery 3.5.0 or later, which patches the vulnerability completely. For systems unable to upgrade immediately, a temporary workaround involves redefining jQuery.htmlPrefilter as an identity function, though this removes security protections and requires additional HTML sanitization measures using tools like DOMPurify. Organizations should maintain updated CVE database records and implement comprehensive vulnerability scanning to identify and address similar JavaScript security gaps proactively.