CVE-2026-44947: Rancher Auth Bypass Vulnerability

CVE-2026-44947 Overview

CVE-2026-44947 is an authorization flaw in Rancher's legacy Project Role Template Binding (PRTB) reconciler. The reconciler fails to clean up permissions when an administrator removes them from a RoleTemplate. As a result, users retain unauthorized Pod Security Admission (PSA) permissions after those permissions have been revoked. The issue affects Rancher versions 2.13.0 through 2.13.7 and 2.14.0 through 2.14.3. The vulnerability is classified under [CWE-281] (Improper Preservation of Permissions).

Critical Impact
Authenticated users with high privileges can retain Pod Security Admission permissions after administrative revocation, undermining Kubernetes workload isolation and integrity controls.

Affected Products

Rancher 2.13.0 through 2.13.7
Rancher 2.14.0 through 2.14.3
Deployments using legacy PRTB reconciler with Pod Security Admission

Discovery Timeline

2026-06-30 - CVE-2026-44947 published to NVD
2026-07-02 - Last updated in NVD database

Technical Details for CVE-2026-44947

Vulnerability Analysis

Rancher manages multi-tenant Kubernetes access through Project Role Template Bindings. A PRTB associates a user or group with a RoleTemplate scoped to a project. When an administrator edits a RoleTemplate to remove Pod Security Admission rules, the legacy reconciler is expected to withdraw the corresponding cluster-level and project-level permissions from subjects bound through the template.

The reconciler omits the clean-up step for PSA-related permissions. Prior authorization state persists in the backing role bindings even though the source RoleTemplate no longer grants those rights. Subjects therefore continue to satisfy Pod Security Admission enforcement checks and can create or mutate workloads with policies that should have been rescinded.

Exploitation requires an authenticated user with existing high privileges to have received PSA permissions before revocation. The impact concentrates on integrity of workload admission controls rather than confidentiality or availability, aligning with the CVSS integrity-focused metrics.

Root Cause

The root cause is a missing clean-up path in the legacy PRTB reconciler. When RoleTemplate rules are removed, the reconciler does not diff prior and current PSA-related grants, leaving stale RoleBinding or ClusterRoleBinding artifacts intact. This is a permission preservation defect classified under [CWE-281].

Attack Vector

The attack path assumes the user previously held PSA permissions granted through a PRTB. An administrator removes those rules from the RoleTemplate expecting immediate revocation. The reconciler processes the update without deleting residual bindings. The user continues to deploy pods that violate the intended Pod Security Standards, bypassing baseline or restricted profile enforcement in the target namespace.

No verified public exploit code exists for this issue. Refer to the Rancher GitHub Security Advisory GHSA-c4rp-wgqc-mfhc for authoritative technical details.

Detection Methods for CVE-2026-44947

Indicators of Compromise

Users successfully creating pods with privileged, hostPath, or other elevated security contexts after their RoleTemplate PSA rules were removed.
RoleBinding or ClusterRoleBinding objects referencing PSA verbs (use on podsecuritypolicies or PSA label management) that no longer appear in the source RoleTemplate.
Discrepancies between RoleTemplate contents and effective permissions returned by kubectl auth can-i for affected subjects.

Detection Strategies

Audit Rancher management cluster for orphaned bindings tied to modified RoleTemplates using kubectl get rolebindings,clusterrolebindings -A -o yaml.
Compare current PRTB reconciled state against the declared RoleTemplate rules and flag deltas.
Enable Kubernetes API server audit logging and monitor create and update requests on pods that carry restricted security contexts by subjects whose templates were recently changed.

Monitoring Recommendations

Track RoleTemplate modification events in Rancher audit logs and correlate with subsequent pod admission decisions.
Alert on Pod Security Admission warnings or violations from user accounts whose privileges were recently reduced.
Continuously verify that PRTB reconciliation completes without residual bindings after RoleTemplate edits.

How to Mitigate CVE-2026-44947

Immediate Actions Required

Upgrade Rancher to a patched release beyond 2.13.7 for the 2.13.x branch or beyond 2.14.3 for the 2.14.x branch.
Enumerate all RoleTemplates modified to remove PSA permissions since deployment and manually revoke residual bindings for affected subjects.
Rotate or review credentials of any user who held PSA-relevant permissions during the affected window.

Patch Information

SUSE Rancher has published fixes referenced in the GitHub Security Advisory GHSA-c4rp-wgqc-mfhc. Apply the vendor-supplied release that supersedes 2.13.7 and 2.14.3 for your deployment channel.

Workarounds

Manually delete stale RoleBinding and ClusterRoleBinding objects that grant PSA permissions no longer present in the source RoleTemplate.
Recreate PRTBs after RoleTemplate edits to force a full binding rebuild instead of an incremental reconcile.
Restrict membership of high-privilege project roles until the patched Rancher version is deployed.

bash

# Identify RoleBindings tied to a specific PRTB for manual review
kubectl get rolebindings -A -o json | \
  jq '.items[] | select(.metadata.labels["authz.cluster.cattle.io/prtb-owner"] != null) | {name: .metadata.name, ns: .metadata.namespace, roleRef: .roleRef}'

# Remove a stale binding after verifying it is no longer authorized
kubectl delete rolebinding <binding-name> -n <project-namespace>