MyBB Last User's Threads in Profile Plugin 1.2 contains a persistent cross-site scripting vulnerability that allows attackers to inject malicious scripts by crafting thread subjects with script tags. Attackers can create threads with script payloads in the subject field that execute when users visit the attacker's profile page.
Exploitability
AV:NAC:LAT:NPR:LUI:PVulnerable System
VC:NVI:NVA:NSubsequent System
SC:LSI:LSA:N5.1/CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:NInjection