CVE-2026-75033: Rancher: Cross-Cluster Secret Leakage via Namespace projectId Annotation Spoofing
A flaw was found in Rancher Manager. Project Secrets were propagated into a namespace based only on its field.cattle.io/projectId annotation, without verifying that the referenced project belonged to the same downstream cluster. A user able to create namespaces on one cluster could set the annotation to a project ID from another cluster and have that project's secrets copied into a namespace under their control.
This issue affects Rancher: before 2.15.1.
Affected Software
Event History
Frequently Asked Questions
Who can exploit this issue?
A user who can create namespaces on one downstream cluster can exploit it by setting a namespace's field.cattle.io/projectId annotation to a project ID associated with another downstream cluster.
What information could be exposed?
Project Secrets from the referenced project can be copied into a namespace controlled by the attacker. The impact is cross-cluster secret disclosure.
Are affected systems limited to a particular configuration?
The issue affects Rancher Manager versions before 2.15.1 where Project Secrets are propagated based only on the namespace field.cattle.io/projectId annotation. Exploitation requires namespace-creation capability on a downstream cluster.
How can I determine whether suspicious exploitation may have occurred?
Review namespaces for field.cattle.io/projectId annotations that reference projects belonging to a different downstream cluster, and check whether Project Secrets were copied into those namespaces.