CVE-2026-68166 Affecting linux-6.12 package, versions <6.12.107-1~deb12u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.2% (10th percentile)

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  • Snyk IDSNYK-ECHOLATEST-LINUX612-19964117
  • published20 Sept 2026
  • disclosed10 Aug 2026

Introduced: 10 Aug 2026

CVE-2026-68166  (opens in a new tab)

How to fix?

Upgrade Echo:latest linux-6.12 to version 6.12.107-1~deb12u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1