CVE-2026-88808: Fleet agent copies downstream resources with cluster-admin privileges, allowing cross-namespace writes on downstream clusters
A vulnerability has been identified within Rancher Manager where the Fleet agent wrote resources to downstream clusters using its own cluster-admin credentials instead of the ServiceAccount pinned to the deployment. It affects multi-tenancy environments where different tenants share the same downstream clusters, for example different privileged or untrusted teams inside the same organization. This could lead to overwritten configuration files.
This issue affected SUSE Rancher Fleet 0.16 before 0.16.2, 0.15 before 0.15.7, and 0.14 before 0.14.11.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
SUSE Rancher Fleetto a version that resolves this vulnerability.Fixed in 0.16.2 - Upgrade
Upgrade
SUSE Rancher Fleetto a version that resolves this vulnerability.Fixed in 0.15.7 - Upgrade
Upgrade
SUSE Rancher Fleetto a version that resolves this vulnerability.Fixed in 0.14.11
Event History
Frequently Asked Questions
Which deployments are most exposed to this issue?
Multi-tenant environments where different tenants share the same downstream clusters are affected, including environments with privileged or untrusted teams in the same organization. The impact is cross-namespace writes on downstream clusters.
What level of access does an attacker need?
The vulnerability requires low privileges and no user interaction. An attacker able to use the affected Fleet workflow could cause resources to be written with the Fleet agent's cluster-admin credentials rather than the ServiceAccount assigned to the deployment.
Which Fleet releases need remediation?
Affected releases are Fleet 0.16 earlier than 0.16.2, Fleet 0.15 earlier than 0.15.7, and Fleet 0.14 earlier than 0.14.11. Upgrade to the applicable fixed release or later.
What could successful exploitation change?
An attacker could write across namespaces on downstream clusters and overwrite configuration files. The reported impact includes compromise of confidentiality, integrity, and availability.