SUSE Rancher Fleet: Privilege escalation to cluster-admin on the Rancher local cluster
Summary
Rancher Fleet's agent management controller did not sufficiently restrict which kubeconfig secrets a Fleet Cluster object may reference. An authenticated user who can create a Fleet cluster in a namespace they control can associate it with the administrative credentials of the Rancher management (local) cluster. The controller then manages that cluster and runs the user's Fleet content there with elevated privileges, which can lead to full cluster-admin access, exposure of stored secrets including downstream cluster credentials, and disruption of the Rancher management server.
Affected
- SUSE Rancher Fleet 0.16.0 to before 0.16.3
- SUSE Rancher Fleet 0.15.0 to before 0.15.8
- SUSE Rancher Fleet 0.14.0 to before 0.14.12
- SUSE Rancher Fleet 0.13.0 to before 0.13.17
- Possibly older versions (unknown)
Fixed in
- Fleet 0.16.3, 0.15.8, 0.14.12, 0.13.17
- Rancher v2.15.3, v2.14.7, v2.13.11, v2.12.15 (upgrade Rancher and its bundled Fleet together)
Workaround
- No Fleet-side configuration fully prevents this issue; upgrading is strongly recommended.
- Remove the self-service creation of Fleet workspaces for ordinary users via custom global roles, if this fits your tenancy model.
- Restrict write access to fleet.cattle.io clusters and bundles to administrators and trusted operators.
- Do not enable allowUnlabeledKubeConfigSecretNamespaces: true as a mitigation, as it restores the vulnerable behaviour.
Exploitation
- No confirmed exploitation in the wild known at the time of research.
- No public proof of concept found.
- CISA SSVC: exploitation none, automatable no, technical impact total.
- VulDB lists the status as 0-Day with a market price estimate; this is not evidence of active exploitation.
Our recommendation
- Upgrade Rancher and Fleet to the patched versions listed above, upgrading Rancher and its bundled Fleet together.
- Until patched, restrict who can create Fleet workspaces, clusters and secrets in Rancher.
- After upgrading, check manually registered clusters that use kubeConfigSecretNamespace; label their secrets with fleet.cattle.io/kubeconfig-referenceable-from=<Cluster namespace> or they will no longer be imported.
- Review whether the Rancher UI and API are reachable from the internet and prioritise exposed instances.
- Monitor Rancher audit logs for unexpected Fleet cluster objects and changes to secrets in the management cluster.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- GitHub advisory GHSA-qfmw-gw96-ffcr github.com
- Rancher security advisories and CVEs ranchermanager.docs.rancher.com
- Rancher releases github.com
- VulDB entry 429885 vuldb.com
- Positive Technologies PT-2026-132862 vulners.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 2 Nov 2026, 17:22.
Original description (NVD)
SUSE Rancher Fleet clusters reference a kubeconfig secret that the controller uses to install and manage a Fleet agent on the target cluster. The controller did not sufficiently restrict which kubeconfig secrets a Fleet Cluster object was allowed to reference. As a result, a Fleet cluster defined in a namespace an ordinary user controls could be associated with administrative credentials for the management cluster itself, causing the controller to manage the management cluster on that user's behalf and to run that user's Fleet content there with elevated privileges. This affects SUSE Rancher Fleet 0.16.0 up to 0.16.3, 0.15.0 up to 0.15.8, 0.14.0 up to 0.14.12, 0.13.0 up to 0.13.17 and possible older versions.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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