hoek node module before 4.2.0 and 5.0.x before 5.0.3 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability via 'merge' and 'applyToDefaults' functions, which allows a malicious user to modify the prototype of "Object" via __proto__, causing the addition or modification of an existing property that will exist on all objects.
https://snyk.io/vuln/npm:hoek:20180212
https://nodesecurity.io/advisories/566
https://hackerone.com/reports/310439
https://github.com/hapijs/hoek/commit/32ed5c9413321fbc37da5ca81a7cbab693786dee
https://access.redhat.com/errata/RHSA-2018:1264