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TI-2026-15370 Aliases CVE-2026-18756

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

Priority LOW 34CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Active
Attack complexity
Low
Attack requirements
Present
Impact type
Cross-site scripting
Confidentiality · integrity · availability
High · High · None
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00467 40th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
humhubHumHub1.18.4—No fix listedCNA
  • HumHub Vendorhumhub Affected 1.18.4 Fixed in — No fix listed CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:humhub:humhub:*:*:*:*:*:*:*:*——humhub
  • cpe:2.3:a:humhub:humhub:*:*:*:*:*:*:*:* Versions — — ·humhub

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-18756

References

Patch 1

Advisory 1

Other 1

  • TI-2026-15145 HumHub 1.18.4 - Stored XSS in comment-deletion notifications through unescaped administrator reason CVSS 4.0HIGH 7.2
  • TI-2022-08676 Improper access control in humhub CVSS 3.1MEDIUM 6.5
  • TI-2017-14097 HumHub Reflected cross site scriting CVSS 3.1MEDIUM 6.1
  • TI-2025-34545 Files: Potential for SQL Injection through File Browse and List Operations CVSS 4.0CRITICAL 9.2
  • TI-2017-14099 HumHub privileges management CVSS 3.1CRITICAL 9.8
  • TI-2024-34921 User enumeration in HubHub CVSS 4.0MEDIUM 6.9
See all 24 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences