CVE-2025-38523 is a medium severity vulnerability in the Linux kernel's CIFS client code related to the smbd_response slab cache. The flaw causes a kernel oops when CONFIG_HARDENED_USERCOPY is enabled due to improper marking of the packet field for usercopy operations. This leads to a kernel memory exposure attempt detection and a crash during data copying from the smbd_response structure to a folio buffer. The issue is fixed by adjusting slab creation parameters to allow safe usercopy from the packet region.