CVE-2025-68283

Vulnerability

CVE-2025-68283 is a vulnerability in the Linux kernel's Ceph filesystem client library (libceph). The root cause is that OSD (Object Storage Device) index values received in network packets were not validated before being used in certain code paths. The kernel code contained a BUG_ON statement that assumed these indices were always valid, but since they originate from untrusted network sources, an attacker could supply a crafted packet with an out-of-bounds OSD index.

Exploitation

An attacker who can send malicious Ceph network messages to a system running an affected kernel can trigger the BUG_ON by providing an OSD index that exceeds map->max_osd. This requires the ability to communicate with the Ceph client, but no authentication is mentioned as a prerequisite; the input is simply parsed from the network without validation.

Impact

A successful exploit results in a kernel panic, leading to a denial of service (DoS) on the affected system. No privilege escalation or data compromise is described. The vulnerability is reachable without authentication if the attacker can send packets to the Ceph client.

Mitigation

The fix replaces the BUG_ON with a proper bounds check, gracefully handling out-of-range OSD indices. The patch also includes adjustments to ceph_get_primary_affinity() and minor cosmetic cleanup [1]. The fix is included in the stable kernel tree [2]. Users should update to a patched kernel version.