This affects the package jszip before 3.7.0. Crafting a new zip file with filenames set to Object prototype values (e.g __proto__, toString, etc) results in a returned object with a modified prototype instance.
https://snyk.io/vuln/SNYK-JS-JSZIP-1251497
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1251498
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARS-1251499
https://github.com/Stuk/jszip/pull/766
https://github.com/Stuk/jszip/commit/22357494f424178cb416cdb7d93b26dd4f824b36
https://github.com/Stuk/jszip/blob/master/lib/object.js%23L88