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Fencer Vulns
high 7.8

CVE-2025-39727 json

mm: swap: fix potential buffer overflow in setup_clusters()

published 2025-09-07 14 mo ago modified 2026-10-19 20 d ago also EUVD-2025-31502

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:

mm: swap: fix potential buffer overflow in setup_clusters()

In setup_swap_map(), we only ensure badpages are in range (0, last_page]. As maxpages might be < last_page, setup_clusters() will encounter a buffer overflow when a badpage is >= maxpages.

Only call inc_cluster_info_page() for badpage which is < maxpages to fix the issue.

Patch / fix

  • Linux Linux 6.12.42, 6.15.10, 6.16.1, 6.17
  • linux Debian 13 6.12.43-1
  • linux Debian 14 6.16.3-1

debian advisories DEBIAN-CVE-2025-39727

  • linux-aws-6.14 Ubuntu 24.04 LTS 6.14.0-1017.17~24.04.1
  • linux-gcp-6.14 Ubuntu 24.04 LTS 6.14.0-1020.21~24.04.1
  • linux-oem-6.14 Ubuntu 24.04 LTS 6.14.0-1016.16
  • linux-azure-6.14 Ubuntu 24.04 LTS 6.14.0-1017.17~24.04.1
  • linux-riscv-6.14 Ubuntu 24.04 LTS 6.14.0-36.36.1~24.04.1
  • linux-oracle-6.14 Ubuntu 24.04 LTS 6.14.0-1017.17~24.04.1
  • linux-realtime-6.14 Ubuntu Pro Realtime 24.04 LTS 6.14.0-1016.16~24.04.1

ubuntu advisories UBUNTU-CVE-2025-39727

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 10.1 6.12.0-124.9.1.el10_1
  • rv RHEL 10.1 6.12.0-124.9.1.el10_1
  • perf RHEL 10.1 6.12.0-124.9.1.el10_1
  • rtla RHEL 10.1 6.12.0-124.9.1.el10_1
  • libperf RHEL 10.1 6.12.0-124.9.1.el10_1
  • kernel-rt RHEL 10.1 6.12.0-124.9.1.el10_1
  • kernel-64k RHEL 10.1 6.12.0-124.9.1.el10_1
  • kernel-core RHEL 10.1 6.12.0-124.9.1.el10_1

red hat advisories RHSA-2025:21118RHSA-2025:19106

  • kernel-rt Linux Micro 6.2 6.12.0-160000.6.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.6.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1.160000.2.4
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.6.1
  • kernel-kvmsmall SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.6.1

suse advisories SUSE-SU-2025:21074-1SUSE-SU-2025:21139-1SUSE-SU-2026:20560-1SUSE-SU-2025:21179-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.6.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.6.1

opensuse advisories openSUSE-SU-2025:20081-1

  • kernel Rocky Linux 10 6.12.0-55.41.1.el10_0

rocky linux advisories RLSA-2025:19106

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-2025-39727 updated cvss 7.3

kernel: mm: swap: fix potential buffer overflow in setup_clusters()

  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-124.9.1.el10_1, rv 6.12.0-55.41.1.el10_0, perf 6.12.0-124.9.1.el10_1, perf 6.12.0-55.41.1.el10_0, rtla 6.12.0-124.9.1.el10_1, rtla 6.12.0-55.41.1.el10_0, +20 more Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-124.9.1.el10_1, kernel 6.12.0-55.41.1.el10_0, kernel-64k 6.12.0-124.9.1.el10_1, kernel-64k 6.12.0-55.41.1.el10_0, kernel-core 6.12.0-124.9.1.el10_1, kernel-core 6.12.0-55.41.1.el10_0, +61 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-124.9.1.el10_1, libperf 6.12.0-55.41.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-124.9.1.el10_1, kernel-debuginfo-common-s390x 6.12.0-55.41.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-124.9.1.el10_1, kernel-debuginfo-common-x86_64 6.12.0-55.41.1.el10_0, +4 more Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-124.9.1.el10_1, kernel-rt 6.12.0-55.41.1.el10_0, kernel-rt-64k 6.12.0-124.9.1.el10_1, kernel-rt-64k 6.12.0-55.41.1.el10_0, kernel-rt-core 6.12.0-124.9.1.el10_1, kernel-rt-core 6.12.0-55.41.1.el10_0, +34 more Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-124.9.1.el10_1, kernel-rt 6.12.0-55.41.1.el10_0, kernel-rt-kvm 6.12.0-55.41.1.el10_0, kernel-rt-core 6.12.0-124.9.1.el10_1, kernel-rt-core 6.12.0-55.41.1.el10_0, kernel-rt-modules 6.12.0-124.9.1.el10_1, +16 more
    fixed: vendor fix RHSA-2025:19106
  • 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 rv, perf, rtla, kernel, bpftool, libperf, +83 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

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
  • CWE-120 Buffer Copy without Checking Size of Input
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.