Why outdated front end libraries are a real risk
Front end JavaScript libraries such as jQuery, Lodash, Moment, and Angular ship to every visitor who loads your page. That is the whole point of them, and it is also where the risk comes from. When a vulnerability is published for a specific version range, the affected code is already sitting in your visitors' browsers, and the version you serve is plainly readable from the page. An attacker does not need to guess. They can match your version to a published advisory and reuse a working exploit against your users.
These issues are not theoretical. Every version of jQuery before 3.5.0 is affected by the htmlPrefilter cross site scripting flaws tracked as CVE-2020-11022 and CVE-2020-11023, where HTML passed to methods like .html() or .append() can execute attacker controlled code even after it looks sanitized. Lodash before 4.17.12 carries the prototype pollution flaw CVE-2019-10744, where a crafted payload reaches Object.prototype and quietly changes behavior across the whole application. Both are trivial to weaponize once an attacker confirms the version you are running.
How to fix vulnerable JavaScript libraries
Start by updating each flagged library to a current release that sits past the affected range, then confirm nothing in your code relied on the old behavior. Remove libraries you no longer use, since a dependency that is loaded but never called is still attack surface that ships to every browser. Pin exact versions in your build so a known good file is served every time rather than whatever a loose range happens to resolve to. For any library you load from a public CDN, add a Subresource Integrity hash so the browser refuses to run a file that has been altered, which protects you even if the CDN itself is compromised.
SiteSecurityScore detects these libraries from the live page in seconds, reports the exact version it found, and points you at the advisory so you know what you are fixing and why. Run the check above, then use the security headers checker to tighten the rest of your front end defenses.