CVE-2026-18756
HighCVSS 7.2Exploitation Probability (EPSS)
Low risk27th percentile - higher than 27% of all known CVEs
Summary
HumHub Community Edition 1.18.4 contains a reflected XSS vulnerability in the space membership-request workflow. An attacker can place attacker-controlled button configuration in the options query-string parameter of the request-membership-form, lure an authenticated non-member into submitting the legitimate form, and cause the server to return JavaScript containing attacker-controlled code.
Risk Assessment
The risk involves potential execution of malicious scripts in the victim's browser, which could lead to session theft, account takeover, or other attacks in the context of the logged-in user.
Recommendation
It is recommended to update HumHub to the latest version that fixes this vulnerability and to validate and sanitize input in query parameters.
Other vulnerabilities in HumHub
See all- CVE-2026-93769High
HumHub 1.18.5 is affected by a stored cross-site scripting (XSS) vulnerability that allows any user holding the delegated, non-system-administrator Manage Users permission (admin_manage_users) to inject persistent HTML/JavaScript into a Profile Field Category title.
- CVE-2026-18430High
HumHub 1.18.4 contains a stored cross-site scripting (XSS) vulnerability in the comment-deletion notification flow. A Space administrator can delete another user's comment, choose to notify the original author, and place HTML/JavaScript in the deletion reason.
- CVE-2026-18526High
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.
- CVE-2026-47657High
Vulnerability in HumHub (enterprise social network) allows any authenticated user to remove all members from any Space, regardless of their role. Missing access control in the member management controller.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS