CVE-2026-40196 HIGH

CVE-2026-40196: HomeBox has Unauthorized API Access via Retained defaultGroup ID After Group Access Revocation

Vendor Sysadminsmedia
Product homebox
Weakness CWE-708
Published April 17, 2026
Last update April 20, 2026

CVSS base score

8.1/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

What the vulnerability does

01Description

HomeBox is a home inventory and organization system. Versions prior to 0.25.0 contain a vulnerability where the defaultGroup ID remained permanently assigned to a user after being invited to a group, even after their access to that group was revoked. While the web interface correctly enforced the access revocation and prevented the user from viewing or modifying the group's contents, the API did not. Because the original group ID persisted as the user's defaultGroup, and this value was not properly validated when the X-Tenant header was omitted, the user could still perform full CRUD operations on the group's collections through the API, bypassing the intended access controls. This issue has been fixed in version 0.25.0.

Key dates

02Disclosure timeline

April 17, 2026 CVE published
April 20, 2026 Record updated