CVE-2026-47657 in HumHub
Summary
by MITRE • 07/21/2026
HumHub is an Open Source Enterprise Social Network. In versions 1.13.0 through 1.18.2, a missing authorization check in the Space member management controller allowed any authenticated user to trigger the removal of all members from any Space, regardless of their own role or membership in that Space. Versions 1.13.0 through 1.18.2 are affected. The vulnerability has been patched in version 1.18.3, and all users are encouraged to upgrade to this version or later immediately. No known workaround is available.
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Analysis
by VulDB Data Team • 07/21/2026
This vulnerability represents a critical authorization flaw in the HumHub social network platform that fundamentally undermines the security model of space membership management. The issue stems from a missing authorization check within the Space member management controller, specifically in versions ranging from 1.13.0 through 1.18.2. This oversight allows any authenticated user to execute destructive actions against spaces they may not even belong to, creating a severe privilege escalation vector that directly violates core security principles of access control and least privilege enforcement.
The technical implementation flaw manifests as an absence of proper permission validation when processing member removal requests through the space management interface. When an authenticated user attempts to trigger the removal of all members from any given space, the system fails to verify whether the requesting user possesses the necessary administrative privileges or even membership status within that particular space. This missing authorization check creates a direct pathway for unauthorized users to manipulate space membership lists, effectively enabling them to completely purge all members from any accessible space within the platform.
The operational impact of this vulnerability extends beyond simple data integrity concerns, as it fundamentally compromises the collaborative environment that HumHub aims to provide. Any authenticated user can now systematically remove all members from spaces they do not control, potentially disrupting organizational workflows, destroying community structures, and causing significant business disruption. This capability particularly affects enterprise environments where spaces may contain sensitive information, project teams, or restricted access groups. The vulnerability essentially grants arbitrary users the ability to perform mass membership deletions that could lead to complete loss of collaboration within affected spaces.
From a cybersecurity perspective, this vulnerability maps directly to CWE-863, which addresses "Incorrect Authorization" and represents a classic example of how insufficient access control validation can create severe security implications. The flaw also aligns with ATT&CK technique T1484.001 related to "Create or Modify System Process" and potentially T1566 for social engineering attacks that could exploit this vulnerability. Organizations using affected versions face immediate risk of unauthorized modifications to their collaborative spaces, with potential cascading effects on business continuity and data governance policies.
The remediation approach requires immediate upgrading to version 1.18.3 or later, as no effective workaround exists for this authorization bypass. System administrators should conduct comprehensive audits of space membership configurations following the upgrade to verify that no unauthorized modifications occurred during the vulnerable period. Security teams should also implement monitoring for unusual membership modification patterns and consider implementing additional access controls or network segmentation measures to limit exposure while upgrading systems. The patch addresses the core authorization check issue by ensuring proper validation occurs before any member removal operations are executed, thereby restoring the intended access control semantics of the platform's space management functionality.