userfaultfd: prevent registration of special VMAs (Linux Linux)

CVE-2026-68166
Not available

At a glance

Source
NVD
EPSS
EPSS 0.21 % · percentile 11 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Received

Description

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.

References

European references

CERT-FR advisories

Affected products

ProductVersions
Linux · Linuxaffected 54007f818206dc27309ca423df4c87dd160a7208 < d974b4b786214883bd8e56bda10b454c80fd6205 ; affected 54007f818206dc27309ca423df4c87dd160a7208 < 495a28d5a100be1b232633f4c2dcc42ba10b3796 ; affected 54007f818206dc27309ca423df4c87dd160a7208 < 165613191ad9d034bf17c00e3a142f9561597ec5 ; affected 54007f818206dc27309ca423df4c87dd160a7208 < 0c26202b157f1efc3cd2f26f5c30f59b508a6a5d ; affected 54007f818206dc27309ca423df4c87dd160a7208 < 3c58f641e813c3c71039f8fd4d4e2a3aab713288
Linux · Linuxaffected 6.6 ; unaffected 0 < 6.6 ; unaffected 6.6.153 ≤ 6.6.* ; unaffected 6.12.105 ≤ 6.12.* ; unaffected 6.18.44 ≤ 6.18.* ; unaffected 7.1.6 ≤ 7.1.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD