Linux Kernel EUVD-2026-38830

Vendor-released patch: upgrade to a fixed stable kernel - 5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33, or 7.0.10 or later on the corresponding branch (apply your distribution's backported kernel update). The fix simply adds the missing ceph_buffer_put() on old_blob in __ceph_setxattr(); the per-branch commits are available at https://git.kernel.org/stable/c/521e5aba857fd267624892c8dd6295f22ce0267e and the related git.kernel.org/stable references. If patching cannot be done immediately, the practical compensating control is to limit exposure of the CephFS client: restrict which users can access CephFS mounts and set xattrs, or avoid mounting Ceph filesystems on untrusted multi-tenant hosts - the trade-off is reduced functionality for workloads that legitimately rely on CephFS xattrs. Because impact is a gradual kernel memory leak, monitoring slab/kernel memory usage and scheduling periodic reboots can bound the effect until the patch is deployed.