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Fencer Vulns
high 7.8

CVE-2026-64017 json

blk-mq: pop cached request if it is usable

published 2026-07-19 3 mo ago modified 2026-10-30 9 d ago also EUVD-2026-45590

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

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

blk-mq: pop cached request if it is usable

When submitting a bio to blk-mq, if the task should sleep after peeking a cached request, but before it pops it, the plug flushes and calls blk_mq_free_plug_rqs, freeing the cached_rqs. This creates a use-after-free bug. Fix this by popping the cached request before any possible blocking calls if it is suitable for use.

Popping this request first holds a queue reference, so avoid any serialization races with queue freezes and can safely proceed with dispatching that request to the driver. This potentially increases a timing window from when a driver wants to freeze its queue to when requests stop being dispatched. That scenario is off the fast path though, and drivers need to appropriately handle requests during a freeze request anyway.

The downside is the popped element needs to be individually freed when we performed a bio plug merge. The cached request would have had to be freed later anyway, but this patch does it inline with building the plug list instead of after flushing it.

Patch / fix

  • Linux Linux 6.1.191, 6.6, 6.6.161, 6.12.104, 6.18.45, 7.0.11, 7.1
  • linux Debian 13 6.12.105-1
  • linux Debian 14 7.0.12-1
  • linux-6.12 Debian 12 6.12.107-1~deb12u1

debian advisories DEBIAN-CVE-2026-64017

  • 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-2026-64017

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 10.2 6.12.0-211.49.1.el10_2
  • rv RHEL 10.2 6.12.0-211.49.1.el10_2
  • perf RHEL 10.2 6.12.0-211.49.1.el10_2
  • rtla RHEL 10.2 6.12.0-211.49.1.el10_2
  • libperf RHEL 10.2 6.12.0-211.49.1.el10_2
  • kernel-rt RHEL 10.2 6.12.0-211.49.1.el10_2
  • kernel-64k RHEL 10.2 6.12.0-211.49.1.el10_2
  • kernel-core RHEL 10.2 6.12.0-211.49.1.el10_2

red hat advisories RHSA-2026:75560RHSA-2026:70484RHSA-2026:57251RHSA-2026:47040

  • kernel-rt Linux Micro 6.2 6.12.0-160000.38.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.38.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1.160000.2.23
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1
  • kernel-azure SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.38.1
  • kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.38.1

suse advisories SUSE-SU-2026:23887-1SUSE-SU-2026:23902-1SUSE-SU-2026:23897-1SUSE-SU-2026:23881-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.38.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.38.1

opensuse advisories openSUSE-SU-2026:21910-1

  • kernel AlmaLinux 10 6.12.0-211.49.1.el10_2
  • rv AlmaLinux 10 6.12.0-211.49.1.el10_2
  • perf AlmaLinux 10 6.12.0-211.49.1.el10_2
  • rtla AlmaLinux 10 6.12.0-211.49.1.el10_2
  • libperf AlmaLinux 10 6.12.0-211.49.1.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.49.1.el10_2
  • kernel-64k AlmaLinux 10 6.12.0-211.49.1.el10_2
  • kernel-core AlmaLinux 10 6.12.0-211.49.1.el10_2

almalinux advisories ALSA-2026:57251ALSA-2026:47040

  • kernel Rocky Linux 10 6.12.0-211.49.1.el10_2
  • kernel Rocky Linux 9 5.14.0-687.31.1.el9_8

rocky linux advisories RLSA-2026:57251RLSA-2026:47040

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-2026-64017 updated cvss 7.0

kernel: blk-mq: pop cached request if it is usable

  • 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: no fix available
  • Red Hat CodeReady Linux Builder EUS (v.9.6) libperf 5.14.0-570.142.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.142.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.142.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.142.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.142.1.el9_6
    fixed: vendor fix RHSA-2026:70484
  • 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 6.12.0-211.49.1.el10_2, perf 6.12.0-211.49.1.el10_2, rtla 6.12.0-211.49.1.el10_2, python3-perf 6.12.0-211.49.1.el10_2, kernel-devel-matched 6.12.0-211.49.1.el10_2, kernel-64k-devel-matched 6.12.0-211.49.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:57251
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) perf 5.14.0-284.200.1.el9_2, rtla 5.14.0-284.200.1.el9_2, kernel-devel-matched 5.14.0-284.200.1.el9_2, kernel-64k-devel-matched 5.14.0-284.200.1.el9_2, kernel-debug-devel-matched 5.14.0-284.200.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.200.1.el9_2, +5 more
    fixed: vendor fix RHSA-2026:92993
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) rv 5.14.0-427.158.1.el9_4, perf 5.14.0-427.158.1.el9_4, rtla 5.14.0-427.158.1.el9_4, kernel-devel-matched 5.14.0-427.158.1.el9_4, kernel-64k-devel-matched 5.14.0-427.158.1.el9_4, kernel-debug-devel-matched 5.14.0-427.158.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:91489
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) rv 6.12.0-55.108.1.el10_0, perf 6.12.0-55.108.1.el10_0, rtla 6.12.0-55.108.1.el10_0, python3-perf 6.12.0-55.108.1.el10_0, kernel-devel-matched 6.12.0-55.108.1.el10_0, kernel-64k-devel-matched 6.12.0-55.108.1.el10_0, +7 more
    fixed: vendor fix RHSA-2026:75560
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) rv 5.14.0-570.142.1.el9_6, perf 5.14.0-570.142.1.el9_6, rtla 5.14.0-570.142.1.el9_6, python3-perf 5.14.0-570.142.1.el9_6, kernel-devel-matched 5.14.0-570.142.1.el9_6, kernel-64k-devel-matched 5.14.0-570.142.1.el9_6, +7 more
    fixed: vendor fix RHSA-2026:70484
show 22 more
  • 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, +27 more
    fixed: vendor fix RHSA-2026:47040
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.49.1.el10_2, kernel-64k 6.12.0-211.49.1.el10_2, kernel-core 6.12.0-211.49.1.el10_2, kernel-tools 6.12.0-211.49.1.el10_2, kernel-modules 6.12.0-211.49.1.el10_2, kernel-64k-core 6.12.0-211.49.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:57251
  • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool 7.0.0-284.200.1.el9_2, kernel 5.14.0-284.200.1.el9_2, kernel-64k 5.14.0-284.200.1.el9_2, kernel-core 5.14.0-284.200.1.el9_2, kernel-tools 5.14.0-284.200.1.el9_2, python3-perf 5.14.0-284.200.1.el9_2, +28 more
    fixed: vendor fix RHSA-2026:92993
  • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool 7.3.0-427.158.1.el9_4, kernel 5.14.0-427.158.1.el9_4, kernel-64k 5.14.0-427.158.1.el9_4, kernel-core 5.14.0-427.158.1.el9_4, kernel-tools 5.14.0-427.158.1.el9_4, python3-perf 5.14.0-427.158.1.el9_4, +28 more
    fixed: vendor fix RHSA-2026:91489
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel 6.12.0-55.108.1.el10_0, kernel-64k 6.12.0-55.108.1.el10_0, kernel-core 6.12.0-55.108.1.el10_0, kernel-tools 6.12.0-55.108.1.el10_0, kernel-modules 6.12.0-55.108.1.el10_0, kernel-64k-core 6.12.0-55.108.1.el10_0, +27 more
    fixed: vendor fix RHSA-2026:75560
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel 5.14.0-570.142.1.el9_6, kernel-64k 5.14.0-570.142.1.el9_6, kernel-core 5.14.0-570.142.1.el9_6, kernel-tools 5.14.0-570.142.1.el9_6, kernel-modules 5.14.0-570.142.1.el9_6, kernel-64k-core 5.14.0-570.142.1.el9_6, +27 more
    fixed: vendor fix RHSA-2026:70484
  • 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 6.12.0-211.49.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.49.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.49.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.49.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.49.1.el10_2
    fixed: vendor fix RHSA-2026:57251
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) libperf 6.12.0-55.108.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.108.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.108.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.108.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.108.1.el10_0
    fixed: vendor fix RHSA-2026:75560
  • 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 6.12.0-211.49.1.el10_2, kernel-rt-64k 6.12.0-211.49.1.el10_2, kernel-rt-core 6.12.0-211.49.1.el10_2, kernel-rt-modules 6.12.0-211.49.1.el10_2, kernel-rt-64k-core 6.12.0-211.49.1.el10_2, kernel-rt-debug-core 6.12.0-211.49.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:57251
  • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt 5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-core 5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-modules 5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-debug-core 5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-modules-core 5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-debug-modules 5.14.0-284.200.1.rt14.485.el9_2, +4 more
    fixed: vendor fix RHSA-2026:93047
  • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt 5.14.0-427.158.1.el9_4, kernel-rt-core 5.14.0-427.158.1.el9_4, kernel-rt-modules 5.14.0-427.158.1.el9_4, kernel-rt-debug-core 5.14.0-427.158.1.el9_4, kernel-rt-modules-core 5.14.0-427.158.1.el9_4, kernel-rt-debug-modules 5.14.0-427.158.1.el9_4, +4 more
    fixed: vendor fix RHSA-2026:91489
  • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt 6.12.0-55.108.1.el10_0, kernel-rt-64k 6.12.0-55.108.1.el10_0, kernel-rt-core 6.12.0-55.108.1.el10_0, kernel-rt-modules 6.12.0-55.108.1.el10_0, kernel-rt-64k-core 6.12.0-55.108.1.el10_0, kernel-rt-debug-core 6.12.0-55.108.1.el10_0, +14 more
    fixed: vendor fix RHSA-2026:75560
  • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt 5.14.0-570.142.1.el9_6, kernel-rt-64k 5.14.0-570.142.1.el9_6, kernel-rt-core 5.14.0-570.142.1.el9_6, kernel-rt-modules 5.14.0-570.142.1.el9_6, kernel-rt-64k-core 5.14.0-570.142.1.el9_6, kernel-rt-debug-core 5.14.0-570.142.1.el9_6, +14 more
    fixed: vendor fix RHSA-2026:70484
  • 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 6.12.0-211.49.1.el10_2, kernel-rt-core 6.12.0-211.49.1.el10_2, kernel-rt-modules 6.12.0-211.49.1.el10_2, kernel-rt-debug-core 6.12.0-211.49.1.el10_2, kernel-rt-modules-core 6.12.0-211.49.1.el10_2, kernel-rt-debug-modules 6.12.0-211.49.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:57251
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt 5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-kvm 5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-core 5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-modules 5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-debug-kvm 5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-debug-core 5.14.0-284.200.1.rt14.485.el9_2, +6 more
    fixed: vendor fix RHSA-2026:93047
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt 5.14.0-427.158.1.el9_4, kernel-rt-kvm 5.14.0-427.158.1.el9_4, kernel-rt-core 5.14.0-427.158.1.el9_4, kernel-rt-modules 5.14.0-427.158.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.158.1.el9_4, kernel-rt-debug-core 5.14.0-427.158.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:91489
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt 6.12.0-55.108.1.el10_0, kernel-rt-kvm 6.12.0-55.108.1.el10_0, kernel-rt-core 6.12.0-55.108.1.el10_0, kernel-rt-modules 6.12.0-55.108.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.108.1.el10_0, kernel-rt-debug-core 6.12.0-55.108.1.el10_0, +6 more
    fixed: vendor fix RHSA-2026:75560
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt 5.14.0-570.142.1.el9_6, kernel-rt-kvm 5.14.0-570.142.1.el9_6, kernel-rt-core 5.14.0-570.142.1.el9_6, kernel-rt-modules 5.14.0-570.142.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.142.1.el9_6, kernel-rt-debug-core 5.14.0-570.142.1.el9_6, +6 more
    fixed: vendor fix RHSA-2026:70484
  • 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
    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

0.13% chance of exploitation in the next 30 days, higher than 2% 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

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.