This affects the package npm-user-validate before 1.0.1. The regex that validates user emails took exponentially longer to process long input strings beginning with @ characters.
https://github.com/npm/npm-user-validate/commit/c8a87dac1a4cc6988b5418f30411a8669bef204e
https://github.com/npm/npm-user-validate/security/advisories/GHSA-xgh6-85xh-479p
Source: MITRE
Published: 2020-10-27
Updated: 2020-10-27
Type: NVD-CWE-noinfo
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 3.9
Severity: HIGH