CVE intelligence

CVE-2026-68166

Vulnerability intelligence

Published Aug 10, 2026Sources checked Oct 28, 2026

N/ACVSS not listedScore unavailable

What this means

Review the available evidence

CVE-2026-68166. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 2, 2026

Release Notes

Vendor-listed releases

6.6.157.1-1

CISA KEVNot listedBased on the latest collected catalog

EPSS0.2%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-68166?

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

userfaultfd: prevent registration of special VMAs

Vova Tokarev says:

userfaultfd allows registration on shadow stack VMAs. With userfaultfd access, you can register on the shadow stack, discard a page ... and inject a page with chosen return addresses via UFFDIO_COPY.

Update vma_can_userfault() to reject VM_SHADOW_STACK.

While on it, also reject VM_SPECIAL so that if a driver would implement vm_uffd_ops, it wouldn't be possible to register special VMAs with userfaultfd.

Since VM_SPECIAL includes VM_DONTEXPAND which is set but hugetlb, exclude hugetlb VMAs from the check for VM_SPECIAL.

Source: NVD