CVE-2026-89652

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

ceph: bound copied dentry name length in NFS export get_name

ceph_get_name() copies the MDS-supplied name into the caller's

NAME_MAX-sized buffer with memcpy(name, rinfo->dname, rinfo->dname_len)

and then writes name[rinfo->dname_len] = 0, without checking dname_len

against NAME_MAX. A malicious or buggy MDS that returns a LOOKUPNAME reply

with dname_len > NAME_MAX overflows the buffer. __get_snap_name() copies

rde->name / rde->name_len the same unchecked way.

Impact: a malicious or compromised Ceph MDS overflows the NAME_MAX name

buffer in a client's NFS-export get_name path, a slab out-of-bounds write

reported by KASAN. Reachable when a CephFS mount is re-exported over NFS.

Add ceph_export_copy_name(), which rejects lengths above NAME_MAX with

-ENAMETOOLONG before the copy, and use it in both ceph_get_name() and

__get_snap_name().

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References