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Fencer Vulns
high 7.8

CVE-2026-31787 json

xen/privcmd: fix double free via VMA splitting

published 2026-04-30 6 mo ago modified 2026-11-06 3 d ago also EUVD-2026-26365

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

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

xen/privcmd: fix double free via VMA splitting

privcmd_vm_ops defines .close (privcmd_close), but neither .may_split nor .open. When userspace does a partial munmap() on a privcmd mapping, the kernel splits the VMA via __split_vma(). Since may_split is NULL, the split is allowed. vm_area_dup() copies vm_private_data (a pages array allocated in alloc_empty_pages()) into the new VMA without any fixup, because there is no .open callback.

Both VMAs now point to the same pages array. When the unmapped portion is closed, privcmd_close() calls: - xen_unmap_domain_gfn_range() - xen_free_unpopulated_pages() - kvfree(pages)

The surviving VMA still holds the dangling pointer. When it is later destroyed, the same sequence runs again, which leads to a double free.

Fix this issue by adding a .may_split callback denying the VMA split.

This is XSA-487 / CVE-2026-31787

Patch / fix

  • Linux Linux 5.10.254, 5.15.204, 6.1.170, 6.6.137, 6.12.85, 6.18.26, 7.0.3, 7.1
  • linux Debian 12 6.1.170-1
  • linux Debian 13 6.12.85-1
  • linux Debian 14 7.0.3-1

debian advisories DEBIAN-CVE-2026-31787

  • linux Ubuntu 22.04 LTS 5.15.0-186.196
  • linux Ubuntu 24.04 LTS 6.8.0-136.136
  • linux Ubuntu 26.04 LTS 7.0.0-27.27
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1112.119
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1008.8
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1112.122
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72

ubuntu advisories UBUNTU-CVE-2026-31787

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 9 5.14.0-687.17.1.el9_8
  • rv RHEL 9 5.14.0-687.17.1.el9_8
  • perf RHEL 9 5.14.0-687.17.1.el9_8
  • rtla RHEL 9 5.14.0-687.17.1.el9_8
  • libperf RHEL 9 5.14.0-687.17.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.17.1.el9_8
  • kernel-64k RHEL 9 5.14.0-687.17.1.el9_8
  • kernel-core RHEL 9 5.14.0-687.17.1.el9_8

red hat advisories RHSA-2026:53989RHSA-2026:52764RHSA-2026:52649RHSA-2026:51603RHSA-2026:51604RHSA-2026:48386

  • kernel-default SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Live Patching 15 SP6 +1 more 6.4.0-150600.23.112.1
  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.55.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.55.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.55.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.55.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.55.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.55.1
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.55.1

suse advisories SUSE-SU-2026:2195-1SUSE-SU-2026:2238-1SUSE-SU-2026:21834-1

  • kernel-source openSUSE Tumbleweed 7.0.3-1.1

opensuse advisories openSUSE-SU-2026:10703-1

  • kernel AlmaLinux 9 5.14.0-687.17.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.17.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.17.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.17.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.17.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.17.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.17.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.17.1.el9_8

almalinux advisories ALSA-2026:27789ALSA-2026:27288ALSA-2026:26427ALSA-2026:26428

  • kernel Rocky Linux 9 5.14.0-687.17.1.el9_8
  • kernel Rocky Linux 10 6.12.0-211.26.1.el10_2
  • kernel Rocky Linux 8 4.18.0-553.134.1.el8_10

rocky linux advisories RLSA-2026:27789RLSA-2026:27288RLSA-2026:26427

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-31787 updated cvss 7.3

kernel: xen/privcmd: fix double free via VMA splitting

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: workaround, no fix available
  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.17.1.el9_8, perf 5.14.0-687.17.1.el9_8, rtla 5.14.0-687.17.1.el9_8, python3-perf 5.14.0-687.17.1.el9_8, kernel-devel-matched 5.14.0-687.17.1.el9_8, kernel-64k-devel-matched 5.14.0-687.17.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:27789
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.26.1.el10_2, perf 6.12.0-211.26.1.el10_2, rtla 6.12.0-211.26.1.el10_2, python3-perf 6.12.0-211.26.1.el10_2, kernel-devel-matched 6.12.0-211.26.1.el10_2, kernel-64k-devel-matched 6.12.0-211.26.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:27288
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) perf 5.14.0-284.186.1.el9_2, rtla 5.14.0-284.186.1.el9_2, kernel-devel-matched 5.14.0-284.186.1.el9_2, kernel-64k-devel-matched 5.14.0-284.186.1.el9_2, kernel-debug-devel-matched 5.14.0-284.186.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.186.1.el9_2, +5 more
    fixed: vendor fix RHSA-2026:51603
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) rv 5.14.0-427.141.1.el9_4, perf 5.14.0-427.141.1.el9_4, rtla 5.14.0-427.141.1.el9_4, kernel-devel-matched 5.14.0-427.141.1.el9_4, kernel-64k-devel-matched 5.14.0-427.141.1.el9_4, kernel-debug-devel-matched 5.14.0-427.141.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:48386
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) rv 6.12.0-55.95.1.el10_0, perf 6.12.0-55.95.1.el10_0, rtla 6.12.0-55.95.1.el10_0, python3-perf 6.12.0-55.95.1.el10_0, kernel-devel-matched 6.12.0-55.95.1.el10_0, kernel-64k-devel-matched 6.12.0-55.95.1.el10_0, +7 more
    fixed: vendor fix RHSA-2026:52764
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.134.1.el8_10, kernel 4.18.0-553.134.1.el8_10, bpftool 4.18.0-553.134.1.el8_10, kernel-core 4.18.0-553.134.1.el8_10, kernel-tools 4.18.0-553.134.1.el8_10, python3-perf 4.18.0-553.134.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:26427
show 28 more
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.17.1.el9_8, kernel-64k 5.14.0-687.17.1.el9_8, kernel-core 5.14.0-687.17.1.el9_8, kernel-tools 5.14.0-687.17.1.el9_8, kernel-modules 5.14.0-687.17.1.el9_8, kernel-64k-core 5.14.0-687.17.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:27789
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.26.1.el10_2, kernel-64k 6.12.0-211.26.1.el10_2, kernel-core 6.12.0-211.26.1.el10_2, kernel-tools 6.12.0-211.26.1.el10_2, kernel-modules 6.12.0-211.26.1.el10_2, kernel-64k-core 6.12.0-211.26.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:27288
  • Red Hat Enterprise Linux BaseOS AUS (v.8.4) perf 4.18.0-305.200.1.el8_4, kernel 4.18.0-305.200.1.el8_4, bpftool 4.18.0-305.200.1.el8_4, kernel-core 4.18.0-305.200.1.el8_4, kernel-tools 4.18.0-305.200.1.el8_4, python3-perf 4.18.0-305.200.1.el8_4, +8 more
    fixed: vendor fix RHSA-2026:47248
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) perf 4.18.0-372.206.1.el8_6, kernel 4.18.0-372.206.1.el8_6, bpftool 4.18.0-372.206.1.el8_6, kernel-core 4.18.0-372.206.1.el8_6, kernel-tools 4.18.0-372.206.1.el8_6, python3-perf 4.18.0-372.206.1.el8_6, +8 more
    fixed: vendor fix RHSA-2026:53989
  • Red Hat Enterprise Linux BaseOS E4S (v.8.8) perf 4.18.0-477.158.1.el8_8, kernel 4.18.0-477.158.1.el8_8, bpftool 4.18.0-477.158.1.el8_8, kernel-core 4.18.0-477.158.1.el8_8, kernel-tools 4.18.0-477.158.1.el8_8, python3-perf 4.18.0-477.158.1.el8_8, +9 more
    fixed: vendor fix RHSA-2026:52649
  • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool 7.0.0-284.186.1.el9_2, kernel 5.14.0-284.186.1.el9_2, kernel-64k 5.14.0-284.186.1.el9_2, kernel-core 5.14.0-284.186.1.el9_2, kernel-tools 5.14.0-284.186.1.el9_2, python3-perf 5.14.0-284.186.1.el9_2, +28 more
    fixed: vendor fix RHSA-2026:51603
  • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool 7.3.0-427.141.1.el9_4, kernel 5.14.0-427.141.1.el9_4, kernel-64k 5.14.0-427.141.1.el9_4, kernel-core 5.14.0-427.141.1.el9_4, kernel-tools 5.14.0-427.141.1.el9_4, python3-perf 5.14.0-427.141.1.el9_4, +28 more
    fixed: vendor fix RHSA-2026:48386
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel 6.12.0-55.95.1.el10_0, kernel-64k 6.12.0-55.95.1.el10_0, kernel-core 6.12.0-55.95.1.el10_0, kernel-tools 6.12.0-55.95.1.el10_0, kernel-modules 6.12.0-55.95.1.el10_0, kernel-64k-core 6.12.0-55.95.1.el10_0, +27 more
    fixed: vendor fix RHSA-2026:52764
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) perf 4.18.0-305.200.1.el8_4, kernel 4.18.0-305.200.1.el8_4, bpftool 4.18.0-305.200.1.el8_4, kernel-core 4.18.0-305.200.1.el8_4, kernel-tools 4.18.0-305.200.1.el8_4, python3-perf 4.18.0-305.200.1.el8_4, +8 more
    fixed: vendor fix RHSA-2026:47248
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) perf 4.18.0-372.206.1.el8_6, kernel 4.18.0-372.206.1.el8_6, bpftool 4.18.0-372.206.1.el8_6, kernel-core 4.18.0-372.206.1.el8_6, kernel-tools 4.18.0-372.206.1.el8_6, python3-perf 4.18.0-372.206.1.el8_6, +8 more
    fixed: vendor fix RHSA-2026:53989
  • Red Hat Enterprise Linux BaseOS TUS (v.8.8) perf 4.18.0-477.158.1.el8_8, kernel 4.18.0-477.158.1.el8_8, bpftool 4.18.0-477.158.1.el8_8, kernel-core 4.18.0-477.158.1.el8_8, kernel-tools 4.18.0-477.158.1.el8_8, python3-perf 4.18.0-477.158.1.el8_8, +8 more
    fixed: vendor fix RHSA-2026:52649
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.17.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.17.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.17.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.17.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.17.1.el9_8
    fixed: vendor fix RHSA-2026:27789
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.26.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.26.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.26.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.26.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.26.1.el10_2
    fixed: vendor fix RHSA-2026:27288
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) libperf 6.12.0-55.95.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.95.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.95.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.95.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.95.1.el10_0
    fixed: vendor fix RHSA-2026:52764
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.134.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.134.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.134.1.el8_10
    fixed: vendor fix RHSA-2026:26427
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.134.1.rt7.475.el8_10, kernel-rt-kvm 4.18.0-553.134.1.rt7.475.el8_10, kernel-rt-core 4.18.0-553.134.1.rt7.475.el8_10, kernel-rt-modules 4.18.0-553.134.1.rt7.475.el8_10, kernel-rt-debug-kvm 4.18.0-553.134.1.rt7.475.el8_10, kernel-rt-debug-core 4.18.0-553.134.1.rt7.475.el8_10, +4 more
    fixed: vendor fix RHSA-2026:26428
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.17.1.el9_8, kernel-rt-64k 5.14.0-687.17.1.el9_8, kernel-rt-core 5.14.0-687.17.1.el9_8, kernel-rt-modules 5.14.0-687.17.1.el9_8, kernel-rt-64k-core 5.14.0-687.17.1.el9_8, kernel-rt-debug-core 5.14.0-687.17.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:27789
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.26.1.el10_2, kernel-rt-64k 6.12.0-211.26.1.el10_2, kernel-rt-core 6.12.0-211.26.1.el10_2, kernel-rt-modules 6.12.0-211.26.1.el10_2, kernel-rt-64k-core 6.12.0-211.26.1.el10_2, kernel-rt-debug-core 6.12.0-211.26.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:27288
  • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt 5.14.0-284.186.1.rt14.471.el9_2, kernel-rt-core 5.14.0-284.186.1.rt14.471.el9_2, kernel-rt-modules 5.14.0-284.186.1.rt14.471.el9_2, kernel-rt-debug-core 5.14.0-284.186.1.rt14.471.el9_2, kernel-rt-modules-core 5.14.0-284.186.1.rt14.471.el9_2, kernel-rt-debug-modules 5.14.0-284.186.1.rt14.471.el9_2, +4 more
    fixed: vendor fix RHSA-2026:51604
  • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt 5.14.0-427.141.1.el9_4, kernel-rt-core 5.14.0-427.141.1.el9_4, kernel-rt-modules 5.14.0-427.141.1.el9_4, kernel-rt-debug-core 5.14.0-427.141.1.el9_4, kernel-rt-modules-core 5.14.0-427.141.1.el9_4, kernel-rt-debug-modules 5.14.0-427.141.1.el9_4, +4 more
    fixed: vendor fix RHSA-2026:48386
  • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt 6.12.0-55.95.1.el10_0, kernel-rt-64k 6.12.0-55.95.1.el10_0, kernel-rt-core 6.12.0-55.95.1.el10_0, kernel-rt-modules 6.12.0-55.95.1.el10_0, kernel-rt-64k-core 6.12.0-55.95.1.el10_0, kernel-rt-debug-core 6.12.0-55.95.1.el10_0, +14 more
    fixed: vendor fix RHSA-2026:52764
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.17.1.el9_8, kernel-rt-core 5.14.0-687.17.1.el9_8, kernel-rt-modules 5.14.0-687.17.1.el9_8, kernel-rt-debug-core 5.14.0-687.17.1.el9_8, kernel-rt-modules-core 5.14.0-687.17.1.el9_8, kernel-rt-debug-modules 5.14.0-687.17.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:27789
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.26.1.el10_2, kernel-rt-core 6.12.0-211.26.1.el10_2, kernel-rt-modules 6.12.0-211.26.1.el10_2, kernel-rt-debug-core 6.12.0-211.26.1.el10_2, kernel-rt-modules-core 6.12.0-211.26.1.el10_2, kernel-rt-debug-modules 6.12.0-211.26.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:27288
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt 5.14.0-284.186.1.rt14.471.el9_2, kernel-rt-kvm 5.14.0-284.186.1.rt14.471.el9_2, kernel-rt-core 5.14.0-284.186.1.rt14.471.el9_2, kernel-rt-modules 5.14.0-284.186.1.rt14.471.el9_2, kernel-rt-debug-kvm 5.14.0-284.186.1.rt14.471.el9_2, kernel-rt-debug-core 5.14.0-284.186.1.rt14.471.el9_2, +6 more
    fixed: vendor fix RHSA-2026:51604
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt 5.14.0-427.141.1.el9_4, kernel-rt-kvm 5.14.0-427.141.1.el9_4, kernel-rt-core 5.14.0-427.141.1.el9_4, kernel-rt-modules 5.14.0-427.141.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.141.1.el9_4, kernel-rt-debug-core 5.14.0-427.141.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:48386
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt 6.12.0-55.95.1.el10_0, kernel-rt-kvm 6.12.0-55.95.1.el10_0, kernel-rt-core 6.12.0-55.95.1.el10_0, kernel-rt-modules 6.12.0-55.95.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.95.1.el10_0, kernel-rt-debug-core 6.12.0-55.95.1.el10_0, +6 more
    fixed: vendor fix RHSA-2026:52764
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.134.1.rt7.475.el8_10, kernel-rt-core 4.18.0-553.134.1.rt7.475.el8_10, kernel-rt-modules 4.18.0-553.134.1.rt7.475.el8_10, kernel-rt-debug-core 4.18.0-553.134.1.rt7.475.el8_10, kernel-rt-debug-modules 4.18.0-553.134.1.rt7.475.el8_10, kernel-rt-modules-extra 4.18.0-553.134.1.rt7.475.el8_10, +2 more
    fixed: vendor fix RHSA-2026:26428
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 d ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.