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Fencer Vulns
high 7.8

CVE-2025-21966 json

dm-flakey: Fix memory corruption in optional corrupt_bio_byte feature

published 2025-04-01 19 mo ago modified 2026-08-05 3 mo ago also EUVD-2025-9354

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 11%
public exploits
0
none known

Summary

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

dm-flakey: Fix memory corruption in optional corrupt_bio_byte feature

Fix memory corruption due to incorrect parameter being passed to bio_init

Patch / fix

  • Linux Linux 6.6.84, 6.12.20, 6.13.8, 6.14
  • linux Debian 14, Debian 13 6.12.20-1

debian advisories DEBIAN-CVE-2025-21966

  • linux Ubuntu 24.04 LTS 6.8.0-84.84
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1039.41
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1040.42
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1036.40
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1037.37
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1038.44
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1023.25
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1039.43

ubuntu advisories UBUNTU-CVE-2025-21966

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 10.0 6.12.0-55.12.1.el10_0
  • rv RHEL 10.0 6.12.0-55.12.1.el10_0
  • perf RHEL 10.0 6.12.0-55.12.1.el10_0
  • rtla RHEL 10.0 6.12.0-55.12.1.el10_0
  • libperf RHEL 10.0 6.12.0-55.12.1.el10_0
  • kernel-rt RHEL 10.0 6.12.0-55.12.1.el10_0
  • kernel-64k RHEL 10.0 6.12.0-55.12.1.el10_0
  • kernel-core RHEL 10.0 6.12.0-55.12.1.el10_0

red hat advisories RHSA-2025:7956RHSA-2025:7903

  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.3.1
  • kernel-syms-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.3.1
  • kernel-source-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.3.1
  • kernel-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.39.1
  • kernel-syms-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.39.1
  • kernel-rt_debug Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.39.1
  • kernel-source-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.39.1
  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.3.1

suse advisories SUSE-SU-2025:01967-1SUSE-SU-2025:01964-1SUSE-SU-2025:01951-1SUSE-SU-2025:01919-1SUSE-SU-2025:01707-1SUSE-SU-2025:01614-1

  • kernel AlmaLinux 9 5.14.0-570.17.1.el9_6
  • rv AlmaLinux 9 5.14.0-570.17.1.el9_6
  • perf AlmaLinux 9 5.14.0-570.17.1.el9_6
  • rtla AlmaLinux 9 5.14.0-570.17.1.el9_6
  • libperf AlmaLinux 9 5.14.0-570.17.1.el9_6
  • kernel-rt AlmaLinux 9 5.14.0-570.17.1.el9_6
  • kernel-64k AlmaLinux 9 5.14.0-570.17.1.el9_6
  • kernel-core AlmaLinux 9 5.14.0-570.17.1.el9_6

almalinux advisories ALSA-2025:7903

  • kernel Rocky Linux 10 6.12.0-55.12.1.el10_0

rocky linux advisories RLSA-2025:7956

  • kernel Azure Linux 3.0 6.6.85.1-2

azure linux advisories AZL-60281

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2025-21966 updated cvss 7.0

kernel: dm-flakey: Fix memory corruption in optional corrupt_bio_byte feature

  • 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
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-570.17.1.el9_6, perf 5.14.0-570.17.1.el9_6, rtla 5.14.0-570.17.1.el9_6, python3-perf 5.14.0-570.17.1.el9_6, kernel-devel-matched 5.14.0-570.17.1.el9_6, kernel-64k-devel-matched 5.14.0-570.17.1.el9_6, +7 more
    fixed: vendor fix RHSA-2025:7903
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-55.12.1.el10_0, perf 6.12.0-55.12.1.el10_0, rtla 6.12.0-55.12.1.el10_0, python3-perf 6.12.0-55.12.1.el10_0, kernel-devel-matched 6.12.0-55.12.1.el10_0, kernel-64k-devel-matched 6.12.0-55.12.1.el10_0, +7 more
    fixed: vendor fix RHSA-2025:7956
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-570.17.1.el9_6, kernel-64k 5.14.0-570.17.1.el9_6, kernel-core 5.14.0-570.17.1.el9_6, kernel-tools 5.14.0-570.17.1.el9_6, kernel-modules 5.14.0-570.17.1.el9_6, kernel-64k-core 5.14.0-570.17.1.el9_6, +27 more
    fixed: vendor fix RHSA-2025:7903
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-55.12.1.el10_0, kernel-64k 6.12.0-55.12.1.el10_0, kernel-core 6.12.0-55.12.1.el10_0, kernel-tools 6.12.0-55.12.1.el10_0, kernel-modules 6.12.0-55.12.1.el10_0, kernel-64k-core 6.12.0-55.12.1.el10_0, +27 more
    fixed: vendor fix RHSA-2025:7956
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-570.17.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.17.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.17.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.17.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.17.1.el9_6
    fixed: vendor fix RHSA-2025:7903
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-55.12.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.12.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.12.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.12.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.12.1.el10_0
    fixed: vendor fix RHSA-2025:7956
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-570.17.1.el9_6, kernel-rt-64k 5.14.0-570.17.1.el9_6, kernel-rt-core 5.14.0-570.17.1.el9_6, kernel-rt-modules 5.14.0-570.17.1.el9_6, kernel-rt-64k-core 5.14.0-570.17.1.el9_6, kernel-rt-debug-core 5.14.0-570.17.1.el9_6, +14 more
    fixed: vendor fix RHSA-2025:7903
show 4 more
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-55.12.1.el10_0, kernel-rt-64k 6.12.0-55.12.1.el10_0, kernel-rt-core 6.12.0-55.12.1.el10_0, kernel-rt-modules 6.12.0-55.12.1.el10_0, kernel-rt-64k-core 6.12.0-55.12.1.el10_0, kernel-rt-debug-core 6.12.0-55.12.1.el10_0, +14 more
    fixed: vendor fix RHSA-2025:7956
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-570.17.1.el9_6, kernel-rt-kvm 5.14.0-570.17.1.el9_6, kernel-rt-core 5.14.0-570.17.1.el9_6, kernel-rt-modules 5.14.0-570.17.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.17.1.el9_6, kernel-rt-debug-core 5.14.0-570.17.1.el9_6, +6 more
    fixed: vendor fix RHSA-2025:7903
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-55.12.1.el10_0, kernel-rt-kvm 6.12.0-55.12.1.el10_0, kernel-rt-core 6.12.0-55.12.1.el10_0, kernel-rt-modules 6.12.0-55.12.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.12.1.el10_0, kernel-rt-debug-core 6.12.0-55.12.1.el10_0, +6 more
    fixed: vendor fix RHSA-2025:7956
  • 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
13 mo ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% 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 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.