# CVE-2026-41050: Rancher Fleet Helm impersonation bypass in RESTClientGetter

Source: https://junglewise.ai/threats/cve-2026-41050-rancher-fleet-helm-impersonation-bypass-in-restclientgetter  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-13. Updated: 2026-05-14  
License: CC BY 4.0 with a link back

CVE-2026-41050 · Severity: critical · CVSS 9.9 · Published 2026-05-13

Rancher Fleet, a tool for managing large-scale Kubernetes cluster deployments, contains a vulnerability that allows users in a multi-tenant environment to bypass security boundaries. An attacker with the ability to push code to a monitored repository can exploit this to read sensitive secrets and configuration data from any namespace across all managed clusters. This could lead to a total compromise of the managed infrastructure and any external services whose credentials are stored within the clusters.

Technologies: [github.com/rancher/fleet (Go)](https://junglewise.ai/threats/technologies/github-com-rancher-fleet), [Suse Fleet](https://junglewise.ai/threats/technologies/fleet). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Suse](https://junglewise.ai/threats/vendors/suse).

## Quick answers

**Is CVE-2026-41050 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-41050 being exploited in the wild.

**How severe is CVE-2026-41050?** Critical severity, with a CVSS score of 9.9, published 13 May 2026.

**Which products and versions are affected?** github.com/rancher/fleet (Go) SEMVER:introduced=0.11.0,fixed=0.11.13,introduced=0.12.0,fixed=0.12.14,introduced=0.13.0,fixed=0.13.10,introduced=0.14.0,fixed=0.14.5,introduced=0.15.0,fixed=0.15.1, SEMVER:introduced=0.15.0,fixed=0.15.1; Suse Fleet >= 0.15.0, < 0.15.1; >= 0.14.0, < 0.14.5; >= 0.13.0, < 0.13.10; >= 0.12.0, < 0.12.14; >= 0.11.0, < 0.11.13.

**Is there a fix for CVE-2026-41050?** Yes. github.com/rancher/fleet (Go): upgrade to 0.15.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-41050 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-41050?** Check whether you run github.com/rancher/fleet (Go) or Suse Fleet at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/rancher/fleet (Go): upgrade to 0.15.1 or later

  ```sh
  go get github.com/rancher/fleet@v0.15.1
  ```


## Technical details

Rancher Fleet's Helm deployer fails to consistently apply ServiceAccount impersonation in two specific code paths: the Helm `lookup` function and the `valuesFrom` directive in `fleet.yaml`. In both cases, the system defaults to using the `fleet-agent`'s high-privilege `cluster-admin` credentials instead of the restricted tenant ServiceAccount. An attacker with 'git push' access to a Fleet-monitored repository can craft malicious Helm charts or configuration files to query the Kubernetes API or reference Secrets and ConfigMaps in unauthorized namespaces. This effectively breaks the multi-tenant isolation boundary, allowing for cross-namespace data exfiltration. The issue is resolved by ensuring the `RESTClientGetter` and Helm action configurations strictly use the impersonated credentials.

## Affected products

- Rancher Fleet >= 0.15.0, < 0.15.1; >= 0.14.0, < 0.14.5; >= 0.13.0, < 0.13.10; >= 0.12.0, < 0.12.14; >= 0.11.0, < 0.11.13

## Identifiers

- CVE-2026-41050
- GHSA-765j-qfrp-hm3j
- GO-2026-5207

## Timeline

- 2026-04-30: disclosed: Initial disclosure to rancher/fleet
- 2026-05-07: advisory: GitHub Advisory published

## References

- [https://api.github.com/users/kodareef5](https://api.github.com/users/kodareef5)
- [https://github.com/kodareef5](https://github.com/kodareef5)
- [https://api.github.com/users/kodareef5/gists%7B/gist_id%7D](https://api.github.com/users/kodareef5/gists%7B/gist_id%7D)
- [https://api.github.com/users/kodareef5/repos](https://api.github.com/users/kodareef5/repos)
- [https://avatars.githubusercontent.com/u/261977334?v=4](https://avatars.githubusercontent.com/u/261977334?v=4)
- [https://api.github.com/users/kodareef5/events%7B/privacy%7D](https://api.github.com/users/kodareef5/events%7B/privacy%7D)

## Related threats

- [Rancher Fleet insecure SSH certificate validation](https://junglewise.ai/threats/cve-2025-23390-fleet-doesn-t-validate-a-server-s-certificate-when-connecting)
- [SUSE Rancher Fleet Pod Security Standards bypass in agent-side deployer](https://junglewise.ai/threats/cve-2026-44938-suse-rancher-fleet-pod-security-standards-bypass-in-agent-side)
- [SUSE Rancher Fleet webhook request forgery via regex injection](https://junglewise.ai/threats/cve-2026-44937-suse-rancher-fleet-webhook-request-forgery-via-regex-injection)
- [SUSE Rancher Fleet credential leak via unvalidated Helm repository URL](https://junglewise.ai/threats/cve-2026-44936-suse-rancher-fleet-credential-leak-via-unvalidated-helm)
- [SUSE Rancher Fleet improper validation in Helm Deployer](https://junglewise.ai/threats/cve-2026-44935-suse-rancher-fleet-improper-validation-in-helm-deployer)