CVE-2026-89652
Summary
by MITRE • 09/11/2026
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().
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