High [CVE-2026-50152] MON subscription handler exposes config-key store to low-privilege CephX users

Ceph is an open-source distributed storage platform providing object, block, and file storage.

In versions prior to 20.2.4 and 19.2.6, the Monitor subscription handler fails to properly authorize access to the configuration-key store, allowing any CephX user with only `mon allow r` capabilities to read the entire store by sending a single crafted MMonSubscribe message.

The config-key store holds sensitive secrets including OSD LUKS disk-encryption passphrases and, on cephadm-managed clusters, the SSH private key that cephadm uses to reach every host in the cluster.

Because that key grants root on every node under the default cephadm configuration, a low-privileged read-only account can escalate to full cluster and host compromise. This issue is fixed in versions 20.2.4 and 19.2.6 A flaw was found in the MON subscription handler of Ceph, a distributed storage system.

Exposure of these secrets can lead to full host-level root access and compromise of encrypted data at rest. The Red Hat Product Security team has assessed the severity of this vulnerability as Important, given that it can be exploited from the adjacent cluster network with low-privilege CephX credentials and no user interaction.

Affected products named by the advisory: Red Hat Ceph Storage 4; Red Hat Ceph Storage 5; Red Hat Ceph Storage 6; Red Hat Ceph Storage 7; and 2 more.