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TI-2026-47946 Aliases CVE-2026-68166GHSA-hv63-47wx-6p3x

userfaultfd: prevent registration of special VMAs

Priority LOW 22Published · Updated

Key facts

Attack vector
—
Privileges required
—
User interaction
—
Attack complexity
—
Impact type
—
Confidentiality · integrity · availability
—
Fix status
Fixed

No CVSS vector from any source. Fix status from CNA and Red Hat.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00206 10th percentileScored 2026-11-07
Fix Fixed Linux (Linux): 6.6.153, 6.12.105, 6.18.44 +2Red Hat: 4 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux6.6 and later6.6.153, 6.12.105, 6.18.44, 7.1.6, 7.2Patch availableCNA
  • Linux VendorLinux Affected 6.6 and later Fixed in 6.6.153, 6.12.105, 6.18.44, 7.1.6, 7.2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*——Linux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 6.6.153, 6.12.105, 6.18.44, 7.1.6, 7.2

Red Hat 4 advisories

  • RHSA-2026:69089 Released 2026-09-21 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) kernel-64k-debug-devel-6.12.0-55.105.1.el10_0, kernel-64k-debug-devel-matched-6.12.0-55.105.1.el10_0, kernel-64k-devel-6.12.0-55.105.1.el10_0 +12
    • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel-6.12.0-55.105.1.el10_0, kernel-64k-6.12.0-55.105.1.el10_0, kernel-64k-core-6.12.0-55.105.1.el10_0 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) kernel-tools-libs-devel-6.12.0-55.105.1.el10_0, libperf-6.12.0-55.105.1.el10_0
    • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt-6.12.0-55.105.1.el10_0, kernel-rt-64k-6.12.0-55.105.1.el10_0, kernel-rt-64k-core-6.12.0-55.105.1.el10_0 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt-6.12.0-55.105.1.el10_0, kernel-rt-core-6.12.0-55.105.1.el10_0, kernel-rt-debug-6.12.0-55.105.1.el10_0 +11
  • RHSA-2026:67720 Released 2026-09-16 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.141.1.el9_6, libperf-5.14.0-570.141.1.el9_6
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.141.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.141.1.el9_6, kernel-64k-devel-5.14.0-570.141.1.el9_6 +12
    • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.141.1.el9_6, kernel-64k-5.14.0-570.141.1.el9_6, kernel-64k-core-5.14.0-570.141.1.el9_6 +28
    • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.141.1.el9_6, kernel-rt-64k-5.14.0-570.141.1.el9_6, kernel-rt-64k-core-5.14.0-570.141.1.el9_6 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.141.1.el9_6, kernel-rt-core-5.14.0-570.141.1.el9_6, kernel-rt-debug-5.14.0-570.141.1.el9_6 +11
  • RHSA-2026:63129 Released 2026-09-04 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.44.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.44.1.el9_8, kernel-64k-devel-5.14.0-687.44.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.44.1.el9_8, kernel-64k-5.14.0-687.44.1.el9_8, kernel-64k-core-5.14.0-687.44.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.44.1.el9_8, libperf-5.14.0-687.44.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.44.1.el9_8, kernel-rt-64k-5.14.0-687.44.1.el9_8, kernel-rt-64k-core-5.14.0-687.44.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.44.1.el9_8, kernel-rt-core-5.14.0-687.44.1.el9_8, kernel-rt-debug-5.14.0-687.44.1.el9_8 +9
Show 1 more Red Hat advisories
  • RHSA-2026:61887 Released 2026-09-01 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.50.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.50.1.el10_2, kernel-64k-devel-6.12.0-211.50.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.50.1.el10_2, kernel-64k-6.12.0-211.50.1.el10_2, kernel-64k-core-6.12.0-211.50.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.50.1.el10_2, libperf-6.12.0-211.50.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.50.1.el10_2, kernel-rt-64k-6.12.0-211.50.1.el10_2, kernel-rt-64k-core-6.12.0-211.50.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.50.1.el10_2, kernel-rt-core-6.12.0-211.50.1.el10_2, kernel-rt-debug-6.12.0-211.50.1.el10_2 +9

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat CodeReady Linux Builder EUS (v.9.6)Fixed RHSA-2026:67720
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:61887
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:63129
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:69089
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:67720
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:61887
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:63129
Red Hat Enterprise Linux BaseOS EUS (v. 10.0)Fixed RHSA-2026:69089
Red Hat Enterprise Linux BaseOS EUS (v.9.6)Fixed RHSA-2026:67720
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:61887
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:63129
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)Fixed RHSA-2026:69089
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:61887
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:63129
Red Hat Enterprise Linux Real Time EUS (v. 10.0)Fixed RHSA-2026:69089
Red Hat Enterprise Linux Real Time EUS (v.9.6)Fixed RHSA-2026:67720
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:61887
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:63129
Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0)Fixed RHSA-2026:69089
Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6)Fixed RHSA-2026:67720
Not affected: 5 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat Enterprise Linux for NVIDIA 26

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-68166
  2. 2026-10-03 Alias added: GHSA-hv63-47wx-6p3x
  3. 2026-11-06 CISA SSVC decision points changed

References

Other 5

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
See all 21741 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences