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GHSA-xr65-5cpm-g36x

CriticalCVSS 9.9 / 10
Published Jul 1, 2026·Last modified Jul 1, 2026
Affected Components(0)

No affected components available

Description

Impact

A vulnerability in Fleet for Rancher Manager affects multi-tenancy environments where different tenants share the same downstream clusters (e.g., different privileged or untrusted teams inside the same organization).

On unpatched versions, tenants could bypass restrictions to access any config map or secret across all namespaces on the downstream cluster. They can create cluster-wide resources using HelmOp or Bundle without authorization. Specifically, an attacker can exploit this vulnerability in the following ways:

  1. Use valuesFrom in fleet.yaml(through a GitRepo resource) or a `HelmOp resource to read the contents of any secret an on the downstream cluster, provided they know or can guess the name, namespace, and key.
  2. Deploy HelmOp and Bundle resources without being restricted to a specific service account for the Fleet agent.

If you use Fleet in a multi-tenant environment, it's recommended that you:

  • Review your cluster and Fleet deployments logs for indicators of unauthorized access across tenant namespaces.
  • Rotate any service accounts and credentials that might have been exposed.

Please consult the associated MITRE ATT&CK - Technique - Unsecured Credentials for further information about this category of attack.

Patches

To resolve this vulnerability, upgrade to a patched version of Fleet. The new Policy resource allows you to:

  • Configure GitRepos, HelmOps, and Bundles to require a specific service account for the Fleet agent on downstream clusters used for deployment. The agent uses these designated service accounts for operations, blocking access to unauthorized resources.
  • Restrict HelmOp repository and chart URLs by using a regular expression. The regular expression is automatically anchored with ^ and $, meaning it must match the entire URL string.

Like GitRepoRestriction, a Policy resource must be created in the specific namespace you want to restrict, and it only applies to that namespace.

Note: Before applying a policy, ensure that the required service account is available on the downstream clusters and is configured with least-privilege permissions.

Patched versions of Fleet include releases v0.15.2, v0.14.6, 0.13.11, and v0.12.15.

Workarounds

If you can't upgrade to a fixed version, please make sure that tenants do not have shared access to the same downstream clusters.

Credits

This security issue was reported by the following collaborators according to our responsible disclosure policy:

  • Radisauskas Arnoldas from NATO and the NATO Cyber Security Centre (NCSC).

References

If you have any questions or comments about this advisory:

Risk Scores
Base Score
9.9

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.

Threat Intelligence
9.1

Active exploitation in the wild has been confirmed. Immediate patching or mitigation is required.

EPSS
0.41%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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