Mantis Bug Tracker (MantisBT) is an open source issue tracker. In version 2.28.0, improper escaping of tag names retrieved from History in Timeline (my_view_page.php) allows an attacker to inject HTML and, if CSP settings permit, achieve execution of arbitrary JavaScript, when displaying a tag that has been renamed or deleted. Version 2.28.1 contains a patch. Workarounds include editing offending History entries (using SQL) and wrapping $this->tag_name in a string_html_specialchars() call in IssueTagTimelineEvent::html().
Exploitability
AV:NAC:LAT:NPR:LUI:PVulnerable System
VC:HVI:HVA:HSubsequent System
SC:NSI:NSA:N8.6/CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NInjection