The package y18n before 3.2.2, 4.0.1 and 5.0.5, is vulnerable to Prototype Pollution.
https://www.oracle.com/security-alerts/cpuApr2021.html
https://snyk.io/vuln/SNYK-JS-Y18N-1021887
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1038306
https://github.com/yargs/y18n/pull/108
https://github.com/yargs/y18n/issues/96
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf