CVE-2026-18756

HumHub Community Edition 1.18.4-pl1 - Reflected XSS in Space membership request button rendering

Published Aug 19, 2026 CVSS 4.0 · 7.2 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title HumHub Community Edition 1.18.4-pl1 - Reflected XSS in Space membership request button rendering
First Time appeared Humhub
Humhub humhub
Weaknesses CWE-79
CPEs cpe:2.3:a:humhub:humhub:1.18.4:*:linux:*:*:*:*:*
cpe:2.3:a:humhub:humhub:1.18.4:*:macos:*:*:*:*:*
cpe:2.3:a:humhub:humhub:1.18.4:*:windows:*:*:*:*:*
Vendors & Products Humhub
Humhub humhub
References
Metrics cvssV4_0

{'score': 7.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Fluid Attacks
Published
Updated
Aug 21, 2026, 4:16 PM
Reserved
Aug 4, 2026, 1:50 AM
Status
Deferred
Published
Aug 19, 2026, 3:16 PM
Modified
Oct 27, 2026, 1:10 PM