HumHub Community Edition 1.18.4 contains a reflected cross-site scripting vulnerability in the Space membership-request workflow. An attacker can place attacker-controlled button configuration in the options query-string parameter of space/membership/request-membership-form, lure an authenticated non-member into submitting the legitimate membership request form, and cause the server to return JavaScript containing attacker-controlled code.

HumHub Community Edition 1.18.4 and 1.18.4-pl1 contain a stored Cross-Site Scripting (XSS) vulnerability in the oEmbed confirmation rendering workflow.