CVE-2026-102406: Authorization Bypass Through User-Controlled Key in Kibana Leading to Cross-Tenant Data Interception
Authorization Bypass Through User-Controlled Key (CWE-639) in Kibana could lead to cross-tenant data interception. In this context, "tenant" refers to a user or team sharing the same Kibana deployment, not a separate Elastic Cloud organization or customer. Kibana's Fleet package installation process allowed a user holding delegated Fleet package-management privileges, without direct Elasticsearch administrative privileges, to claim a data stream identifier already in use by another tenant. Because ownership of that identifier was not verified before Fleet applied the uploaded package's generated index and ingest-pipeline settings to already-existing infrastructure, an attacker could redirect an existing tenant's data stream through infrastructure under their control. This exposed the affected tenant's subsequently ingested data to unauthorized disclosure and modification, and prevented that data from reaching its intended destination. Interception could continue even after the malicious package was removed, requiring separate remediation of the affected infrastructure.
Affected Software
Event History
Frequently Asked Questions
Who is exposed to this issue?
The issue affects tenants that share the same Kibana deployment. “Tenant” in this case means a user or team within that deployment, not separate Elastic Cloud organizations or customers.
What level of access does an attacker need?
An attacker needs delegated Fleet package-management privileges. Direct Elasticsearch administrative privileges are not required.
What can an attacker do after exploiting the issue?
They can claim a data stream identifier already used by another tenant and cause that tenant’s subsequently ingested data to pass through attacker-controlled infrastructure. This can expose data to disclosure and modification and prevent it from reaching its intended destination.
Is removing a malicious Fleet package sufficient to stop the impact?
No. Interception can continue after the malicious package is removed, so the affected infrastructure requires separate remediation.