Medium [CVE-2026-73499] Information disclosure via Watch API authorization bypass
This medium-severity Red Hat Linux advisory covers CVE-2026-73499 affecting Multicluster Global Hub, Red Hat Advanced Cluster Management for Kubernetes 2, Red Hat OpenShift Container Platform 4.
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Summary
A flaw was found in etcd, a distributed key-value store. A user with READ permission on a single key can bypass authorization checks in the Watch gRPC API by using open-ended range requests.
This allows them to receive watch events for keys beyond their authorized scope, leading to information disclosure. This issue affects clusters with authentication enabled.
Red Hat severity: Moderate — CVSS 6.5 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N). Weakness: CWE-551.
Affected Red Hat products: Multicluster Global Hub; Red Hat Advanced Cluster Management for Kubernetes 2; Red Hat OpenShift Container Platform 4; Red Hat OpenShift GitOps; Red Hat OpenStack Platform 16.2; Red Hat OpenStack Platform 17.1; Red Hat OpenStack Platform 18.0.
Red Hat lists Red Hat Ansible Automation Platform 2; Red Hat Ceph Storage 5; Red Hat Ceph Storage 6; Red Hat Ceph Storage 7; Red Hat Ceph Storage 8; Red Hat Ceph Storage 9; Red Hat Hardened Images; Red Hat OpenShift Container Platform 4 as not affected.
Will not fix / out of support: Red Hat Advanced Cluster Management for Kubernetes 2; Red Hat OpenStack Platform 16.2; Red Hat OpenStack Platform 17.1. Red Hat does not currently list a fixing RHSA for this CVE.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
- 3.5.33
- 3.6.14
- 3.7.1
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Mitigation checklist
- If etcd authentication is not required for the deployment, this vulnerability does not apply. For clusters with authentication enabled, restrict network-level access to the etcd gRPC API to trusted clients only, and audit user permissions to ensure the principle of least privilege.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
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