Summary
REBUILD contains a missing authorization vulnerability in the /commons/file-editor-save endpoint, where user-controlled url or fileKey values may be processed without sufficient access checks. A remote attacker who can reach the endpoint may access or modify file-related resources beyond their intended permissions.
Affected context
The issue occurs in REBUILD deployments using the file editor save functionality. Risk is present when the endpoint accepts url or fileKey parameters without consistently verifying that the requesting principal is authorized to access the referenced resource. Exposure depends on network reachability, authentication controls, and the permissions associated with the affected endpoint.
Exploit preconditions
- Attack surface: The remotely reachable
/commons/file-editor-saveendpoint - Required access: Network access to the endpoint; authentication requirements depend on deployment configuration
- Trigger point: Processing of the
urlorfileKeyrequest parameters - Why exploitation is possible: Authorization checks may be absent or insufficient before the requested file operation is performed
Why this happens
The underlying flaw is an authorization-enforcement failure. The endpoint appears to rely on client-supplied resource identifiers without reliably confirming that the current user or session has permission to perform the requested operation. This behavior maps primarily to CWE-862, Missing Authorization, and may also involve CWE-863, Incorrect Authorization, when checks exist but do not correctly validate resource ownership or permitted actions.
Potential impact
- An attacker may access files outside their authorized scope
- An attacker could modify or overwrite file-related resources
- Sensitive application data may be exposed or altered
- Unauthorized changes could affect application behavior or content integrity
- The vulnerability may support follow-on attacks if modified files are later trusted by other components
General mitigation guidance
Mitigation generally focuses on enforcing authorization at the server-side
resource-operation boundary rather than trusting client-supplied identifiers.
Common defensive patterns include:
- Applying deny-by-default authorization checks before every file operation
- Binding resource identifiers to the authenticated principal and permitted scope
- Validating both the requested action and the target resource
- Avoiding direct trust in
urlorfileKeyvalues supplied by clients - Using centralized, consistently enforced authorization policies
- Running the application with the minimum filesystem and service privileges required
- Limiting endpoint exposure and applying network or gateway policy controls where appropriate
How teams detect issues like this
Organizations can look for this class of issue through:
- Static analysis rules identifying sensitive endpoints that use request parameters without nearby authorization checks
- Code review signals such as direct file access based on client-controlled paths or identifiers
- Tests that exercise cross-user and cross-tenant resource access boundaries
- Runtime monitoring for unusual file-save requests, denied-access patterns, and access to unrelated resource identifiers
- Policy enforcement requiring authorization decisions before file, object, or record operations
- Automated security review tools that flag missing or inconsistent access-control checks
