"Clear History and Website Data" did not clear the history. The issue was addressed with improved data deletion. This issue is fixed in macOS Catalina 10.15. A user may be unable to delete browsing history items.
Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:LI:NA:N5.3/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N