CVE-2026-18756

Name of the Vulnerable Software and Affected Versions HumHub Community Edition version 1.18.4

Description A reflected cross-site scripting issue exists in the Space membership-request workflow. An attacker can inject malicious button configuration into the options query-string parameter of the 'space/membership/request-membership-form' endpoint. By tricking an authenticated non-member into submitting the membership request form, the server returns JavaScript containing the attacker-controlled code.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.