CVE-2026-48974 in HomeBox
Summary
by MITRE • 09/21/2026
HomeBox is a home inventory and organization system. Prior to 0.26.0, POST /v1/groups/members invokes HandleGroupMemberAdd and GroupService.AddMember using a caller-supplied userID without requiring an owner role, an invitation token, target-user consent, or target-user notification. Any authenticated user can force another account into the caller's group, disclose the target user's email address and name through the resulting member list, and create the membership prerequisite used by a separate cross-group inventory-wipe vulnerability. This issue is fixed in version 0.26.0.
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Analysis
by VulDB Data Team • 09/21/2026
The vulnerability identified in HomeBox prior to version 0.26.0 represents a critical failure in access control logic within the application's group management subsystem. Specifically, the POST /v1/groups/members endpoint, which is responsible for adding members to existing groups, fails to enforce necessary authorization checks before processing requests. The underlying implementation invokes HandleGroupMemberAdd and GroupService.AddMember using a caller-supplied userID without verifying whether the requesting user possesses an owner role within the target group. Furthermore, the system does not require a valid invitation token, nor does it mandate consent from or notify the targeted user prior to their addition. This architectural flaw allows any authenticated user to unilaterally force another account into a group they control, bypassing standard social and administrative safeguards designed to prevent unauthorized associations between users.
From a technical perspective, this issue is classified as an Authorization Bypass through User-Controlled Key (CWE-284) combined with Improper Access Control (CWE-285). The attacker leverages the lack of server-side validation on the group membership parameters to manipulate the application state arbitrarily. By supplying arbitrary user identifiers in the request payload, the malicious actor exploits the trust placed in client-supplied data without sufficient backend verification against role-based access control policies or consent mechanisms. This aligns with MITRE ATT&CK technique T1078, Valid Accounts, as it involves an authenticated attacker abusing legitimate credentials to perform unauthorized actions that escalate their influence within the application's social graph structure.
The operational impact of this vulnerability extends beyond simple privacy violations and includes significant data disclosure risks. Once a target user is forcibly added to a group controlled by the attacker, the member list becomes accessible to all members of that group due to standard visibility rules in home inventory systems. Consequently, the attacker can extract sensitive personally identifiable information (PII) from the victim's profile, specifically their email address and full name. This data leakage facilitates further reconnaissance activities such as phishing campaigns or credential stuffing attacks against other services where the user may reuse credentials. Additionally, this forced membership creates a structural prerequisite that enables more severe downstream vulnerabilities.
A particularly concerning aspect of this flaw is its role in enabling cross-group inventory-wipe operations. The ability to forcibly add users to groups allows an attacker to manipulate group memberships in ways that trigger logic errors or privilege escalations in related features. Specifically, the forced membership can be used as a stepping stone to exploit separate vulnerabilities involving inventory management across different groups. By controlling the composition of groups through unauthorized additions, attackers can bypass isolation boundaries between distinct household inventories, potentially leading to mass deletion or corruption of data belonging to unrelated users. This demonstrates how an initial access control flaw can serve as a pivot point for broader system compromise and data integrity violations.
To mitigate this vulnerability, organizations running HomeBox must immediately upgrade to version 0.26.0 or later, where the developers have implemented proper authorization checks on the group membership endpoints. For environments unable to patch immediately due to operational constraints, temporary mitigations should focus on restricting access to the affected API endpoint at the network perimeter using a Web Application Firewall (WAF) that validates request origins and enforces strict input filtering for user identifiers. Additionally, implementing rate limiting on member addition requests can reduce the blast radius of automated exploitation attempts. Long-term remediation strategies should include conducting a comprehensive audit of all group-related endpoints to ensure consistent enforcement of role-based access controls and mandatory consent workflows for any action that alters user associations within the system.