This affects the package y18n before 3.2.2, 4.0.1 and 5.0.5. PoC by po6ix: const y18n = require('y18n')(); y18n.setLocale('proto'); y18n.updateLocale({polluted: true}); console.log(polluted); // true (CVE-2020-7774).
The package hosted-git-info before 3.0.8 are vulnerable to Regular Expression Denial of Service (ReDoS) via regular expression shortcutMatch in the fromUrl function in index.js. The affected regular expression exhibits polynomial worst-case time complexity (CVE-2021-23362).
ssri 5.2.2-8.0.0, fixed in 8.0.1, processes SRIs using a regular expression which is vulnerable to a denial of service. Malicious SRIs could take an extremely long time to process, leading to denial of service. This issue only affects consumers using the strict option (CVE-2021-27290).
Theses issues are fixed by upgrading nodejs packages to latest available LTS 14.17.3 version. See upstream releases notes for other included bugfixes.