CVE-2026-44935: Rancher Fleet vulnerable to cross namespace secret disclosure via unvalidated `valuesFrom` references in Helm Deployer

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.5%, percentile 41: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 41% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes github.com/rancher/fleet (Go) >= 0.15.0, < 0.15.2, fixed in 0.15.2; github.com/rancher/fleet (Go) >= 0.14.0, < 0.14.6, fixed in 0.14.6; github.com/rancher/fleet (Go) >= 0.13.0, < 0.13.11, fixed in 0.13.11; github.com/rancher/fleet (Go) >= 0.12.0, < 0.12.15, fixed in 0.12.15. Check your lockfile, including transitive dependencies.

What it is

Missing validation of "valuesFrom" references in Helm Deployer of SUSE Rancher Fleet 0.15 before 0.15.2, 0.14 before 0.14.6, 0.13 before 0.13.11 and 0.12 before 0.12.15 could be used by owners of one tenant to access fleet credentials of other tenants.

From the GitHub advisory

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.

Weakness type: CWE-1287, CWE-863.

Product: github.com/rancher/fleet (Go) · Assigned by: suse · Published: 2026-07-02

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: low (any account)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.49% probability of exploitation activity in the next 30 days; percentile 41.

Timeline

• 2026-07-01 — GitHub-reviewed advisory GHSA-xr65-5cpm-g36x published (critical)
• 2026-07-02 — CVE record published by suse
• 2026-07-03 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. github.com github.com

Vulnerability records

1. GitHub Advisory GHSA-xr65-5cpm-g36x github.com
2. CVE.org record CVE-2026-44935 cve.org
3. NVD entry CVE-2026-44935 nvd.nist.gov

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