Why wordpress only use old jQuery version is 1.12.4?

Likely backwards compatibility. Many themes and plugins rely on the bundled version of jQuery, and 3.x (and probably 2.x) introduces breaking changes that would cause these themes and plugins to break.

If do an audit in Chrome Developer Tools for WordPress 4.9.8 it reports that jQuery 1.12.4 contains a known security vulnerability.

• This reply was modified 6 years, 2 months ago by lwk2431.

Lol, resolved.

I do not think so.

I’ve also always wondered this.

This is clearly not resolved and it would be good to have a better response from @wordpress

Definitely

Would love to know the story as well. It is reported as a security risk, unless WP is doing something to make it safe. I can’t seem to find any info from WP on the rationale to use jquery.js from 2016 and 2013.

https://core.trac.www.ads-software.com/ticket/37110

Security updates ave been backported.

I’m closing this as there’s a trac ticket, and you are encouraged to follow there.