CVE-2026-43073

Technical Description

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

x86-64: rename misleadingly named '__copy_user_nocache()' function

This function was a masterclass in bad naming, for various historical

reasons.

It claimed to be a non-cached user copy. It is literally _neither_ of

those things. It's a specialty memory copy routine that uses

non-temporal stores for the destination (but not the source), and that

does exception handling for both source and destination accesses.

Also note that while it works for unaligned targets, any unaligned parts

(whether at beginning or end) will not use non-temporal stores, since

only words and quadwords can be non-temporal on x86.

The exception handling means that it _can_ be used for user space

accesses, but not on its own - it needs all the normal "start user space

access" logic around it.

But typically the user space access would be the source, not the

non-temporal destination. That was the original intention of this,

where the destina

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. 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.

Affected Products

References