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Fencer Vulns
high 7.8

CVE-2026-52973 json

futex: Drop CLONE_THREAD requirement for private default hash alloc

published 2026-06-24 4 mo ago modified 2026-10-19 20 d ago also EUVD-2026-38841

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

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

futex: Drop CLONE_THREAD requirement for private default hash alloc

Currently need_futex_hash_allocate_default() depends on strict pthread semantics, abusing CLONE_THREAD. This breaks the non-concurrency assumptions when doing the mm->futex_ref pcpu allocations, leading to bugs[0] when sharing the mm in other ways; ie:

BUG: KASAN: slab-use-after-free in futex_hash_put

... where the +1 bias can end up on a percpu counter that mm->futex_ref no longer points at.

Loosen the check to cover any CLONE_VM clone, except vfork(). Excluding vfork keeps the existing paths untouched (no overhead), and we can't race in the first place: either the parent is suspended and the child runs alone, or mm->futex_ref is already allocated from an earlier CLONE_VM.

Patch / fix

  • Linux Linux 6.18.33, 7.0.10, 7.1
  • Red Hat Red Hat Enterprise Linux 10 0:6.12.0-211.39.1.el10_2
  • Red Hat Red Hat Enterprise Linux 9 0:5.14.0-687.31.1.el9_8
  • linux Debian 14 7.0.10-1

debian advisories DEBIAN-CVE-2026-52973

  • linux Ubuntu 26.04 LTS 7.0.0-28.28
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1009.9
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1008.8
  • linux-gke Ubuntu 26.04 LTS 7.0.0-1003.4
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1010.10
  • linux-azure Ubuntu 26.04 LTS 7.0.0-1010.10
  • linux-raspi Ubuntu 26.04 LTS 7.0.0-1015.15
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-28.28.1

ubuntu advisories UBUNTU-CVE-2026-52973

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

  • kpatch-patch-6_12_0-211_16_1 RHEL 10.2 1-8.el10_2
  • kpatch-patch-5_14_0-687_10_1 RHEL 9 1-8.el9_8
  • kernel RHEL 9 5.14.0-687.31.1.el9_8
  • rv RHEL 9 5.14.0-687.31.1.el9_8
  • perf RHEL 9 5.14.0-687.31.1.el9_8
  • rtla RHEL 9 5.14.0-687.31.1.el9_8
  • libperf RHEL 9 5.14.0-687.31.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.31.1.el9_8

red hat advisories RHSA-2026:62642RHSA-2026:62640RHSA-2026:47040RHSA-2026:45114

  • kernel AlmaLinux 9 5.14.0-687.31.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.31.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.31.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.31.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.31.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.31.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.31.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.31.1.el9_8

almalinux advisories ALSA-2026:47040ALSA-2026:45114

  • kernel Rocky Linux 9 5.14.0-687.31.1.el9_8
  • kernel Rocky Linux 10 6.12.0-211.39.1.el10_2

rocky linux advisories RLSA-2026:47040RLSA-2026:45114

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-2026-52973 updated cvss 7.0

kernel: futex: Drop CLONE_THREAD requirement for private default hash alloc

  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.31.1.el9_8, perf 5.14.0-687.31.1.el9_8, rtla 5.14.0-687.31.1.el9_8, python3-perf 5.14.0-687.31.1.el9_8, kernel-devel-matched 5.14.0-687.31.1.el9_8, kernel-64k-devel-matched 5.14.0-687.31.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:47040
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.39.1.el10_2, perf 6.12.0-211.39.1.el10_2, rtla 6.12.0-211.39.1.el10_2, python3-perf 6.12.0-211.39.1.el10_2, kernel-devel-matched 6.12.0-211.39.1.el10_2, kernel-64k-devel-matched 6.12.0-211.39.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:45114
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.31.1.el9_8, kernel-64k 5.14.0-687.31.1.el9_8, kernel-core 5.14.0-687.31.1.el9_8, kernel-tools 5.14.0-687.31.1.el9_8, kernel-modules 5.14.0-687.31.1.el9_8, kernel-64k-core 5.14.0-687.31.1.el9_8, +28 more
    fixed: vendor fix RHSA-2026:47040
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.39.1.el10_2, kernel-64k 6.12.0-211.39.1.el10_2, kernel-core 6.12.0-211.39.1.el10_2, kernel-tools 6.12.0-211.39.1.el10_2, kernel-modules 6.12.0-211.39.1.el10_2, kernel-64k-core 6.12.0-211.39.1.el10_2, +29 more
    fixed: vendor fix RHSA-2026:45114
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.31.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.31.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.31.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.31.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.31.1.el9_8
    fixed: vendor fix RHSA-2026:47040
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.39.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.39.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.39.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.39.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.39.1.el10_2
    fixed: vendor fix RHSA-2026:45114
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.31.1.el9_8, kernel-rt-64k 5.14.0-687.31.1.el9_8, kernel-rt-core 5.14.0-687.31.1.el9_8, kernel-rt-modules 5.14.0-687.31.1.el9_8, kernel-rt-64k-core 5.14.0-687.31.1.el9_8, kernel-rt-debug-core 5.14.0-687.31.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:47040
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.39.1.el10_2, kernel-rt-64k 6.12.0-211.39.1.el10_2, kernel-rt-core 6.12.0-211.39.1.el10_2, kernel-rt-modules 6.12.0-211.39.1.el10_2, kernel-rt-64k-core 6.12.0-211.39.1.el10_2, kernel-rt-debug-core 6.12.0-211.39.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:45114
show 3 more
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.31.1.el9_8, kernel-rt-core 5.14.0-687.31.1.el9_8, kernel-rt-modules 5.14.0-687.31.1.el9_8, kernel-rt-debug-core 5.14.0-687.31.1.el9_8, kernel-rt-modules-core 5.14.0-687.31.1.el9_8, kernel-rt-debug-modules 5.14.0-687.31.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:47040
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.39.1.el10_2, kernel-rt-core 6.12.0-211.39.1.el10_2, kernel-rt-modules 6.12.0-211.39.1.el10_2, kernel-rt-debug-core 6.12.0-211.39.1.el10_2, kernel-rt-modules-core 6.12.0-211.39.1.el10_2, kernel-rt-debug-modules 6.12.0-211.39.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:45114
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more 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
    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
total
Assessed
23 d ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CISA ADP 3.1 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8

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.