The Linux kernel contained a helper named __copy_user_nocache that was a misnomer; it actually performed non‑temporal stores and handled exceptions for both source and destination, but it did not enforce the proper user‑space access checks that a real "copy_user" function would require, constituting an instance of CWE-440: improper restriction on usage of a function. Drivers had been using this routine for various purposes, including performance tweaks and copying from user space into special kernel buffers, without guaranteeing that the source data was trusted or that bounds were respected. The rename and prototype change add proper restrictions to the function, but until the patch is applied or the code is reviewed, code paths that call the routine could inadvertently perform unsafe kernel copies.

All Linux kernel releases that include the __copy_user_nocache helper are affected, which comprises the current and older mainstream kernels until the patch is merged. Users of any distribution running an unpatched kernel should assume that the function is present and may be misused by device drivers or kernel modules that call it directly.

No remote exploitation path is documented in the CVE entry, and the EPSS score is less than 1 %, indicating no widespread known exploitation. The CVSS score of 5.5 reflects a moderate potential impact if a driver incorrectly invokes the helper; however, the risk is largely limited to kernel stability and correctness rather than a high‑severity security flaw. The vulnerability is not listed in the CISA KEV catalog, further supporting that it is not currently actively exploited.