Summary
HomeBox contains an authorization flaw in maintenance-entry update and delete operations, allowing an authenticated low-privileged user to act on records outside the user's active group. If the user knows or can enumerate another tenant's maintenance-entry UUID, they may overwrite or permanently delete that record.
Affected context
The vulnerability occurs in HomeBox deployments where maintenance-entry operations identify records by UUID but do not confirm that the record belongs to the authenticated user's active group. It is relevant to authenticated users with access to the application's maintenance-entry functionality and becomes risky when object identifiers are exposed, predictable, or otherwise obtainable across tenant boundaries.
Exploit preconditions
- Attack surface: Authenticated maintenance-entry update and delete endpoints
- Required access: A valid low-privileged HomeBox user account
- Required knowledge: The UUID of a maintenance entry belonging to another group, whether known or enumerated
- Trigger point: Processing an update or delete request for the selected maintenance entry
- Why exploitation is possible: The repository operations address records directly by identifier without enforcing active-group ownership
Why this happens
The underlying bug is an object-level authorization failure. Update and delete operations use the supplied maintenance-entry identifier as sufficient authority to select a record, while omitting a server-side check that the record belongs to the authenticated user's active group. This maps to CWE-639, Authorization Bypass Through User-Controlled Key, because a user-controlled object key can be used to access a resource outside the user's authorized tenant or scope.
Potential impact
- An attacker may modify maintenance information belonging to another group
- An attacker could permanently delete another tenant's maintenance records
- Data integrity and inventory history may be compromised
- Cross-tenant privacy or operational impacts could result
- The affected account may be used to perform unauthorized actions without elevated privileges
General mitigation guidance
Mitigation generally focuses on enforcing authorization at the resource layer
rather than trusting object identifiers supplied by clients.
Common defensive patterns include:
- Require every update and delete operation to verify active-group ownership or an equivalent authorization policy
- Apply tenant or group scoping directly in repository queries
- Treat UUIDs as identifiers, not as authorization evidence
- Use deny-by-default authorization for cross-group object access
- Minimize account privileges and separate administrative capabilities from ordinary user actions
- Return consistent authorization failures without revealing whether an out-of-scope object exists
- Add automated tests covering cross-tenant access attempts for every CRUD operation
How teams detect issues like this
Organizations can detect this class of issue through:
- Static analysis and code review rules that flag direct update or delete operations based only on user-controlled identifiers
- Review of repository methods for missing tenant, group, owner, or policy predicates
- Authorization tests that attempt access to valid objects from an unrelated group
- API and application logs monitoring repeated requests involving out-of-scope object identifiers
- Policy checks requiring resource authorization before mutation or deletion
- Automated security testing tools that exercise broken object-level authorization scenarios
