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Fencer Vulns
high 8.1

CVE-2025-40133 json

mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable().

published 2025-11-12 11 mo ago modified 2026-10-19 20 d ago also EUVD-2025-124950

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

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

mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable().

mptcp_active_enable() is called from subflow_finish_connect(), which is icsk->icsk_af_ops->sk_rx_dst_set() and it's not always under RCU.

Using sk_dst_get(sk)->dev could trigger UAF.

Let's use __sk_dst_get() and dst_dev_rcu().

Patch / fix

  • Linux Linux 6.12.55, 6.17.3, 6.18
  • linux Debian 13 6.12.57-1
  • linux Debian 14 6.17.6-1

debian advisories DEBIAN-CVE-2025-40133

  • linux Ubuntu 25.10 6.17.0-14.14
  • linux-aws Ubuntu 25.10 6.17.0-1007.7
  • linux-gcp Ubuntu 25.10 6.17.0-1007.7
  • linux-azure Ubuntu 25.10 6.17.0-1008.8
  • linux-raspi Ubuntu 25.10 6.17.0-1008.8
  • linux-riscv Ubuntu 25.10 6.17.0-14.14.1
  • linux-oracle Ubuntu 25.10 6.17.0-1007.7
  • linux-aws-6.17 Ubuntu 24.04 LTS 6.17.0-1007.7~24.04.1

ubuntu advisories UBUNTU-CVE-2025-40133

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 6.12.0-124.35.1.el10_1
  • rv RHEL 10.1 6.12.0-124.35.1.el10_1
  • perf RHEL 10.1 6.12.0-124.35.1.el10_1
  • rtla RHEL 10.1 6.12.0-124.35.1.el10_1
  • libperf RHEL 10.1 6.12.0-124.35.1.el10_1
  • kernel-rt RHEL 10.1 6.12.0-124.35.1.el10_1
  • kernel-64k RHEL 10.1 6.12.0-124.35.1.el10_1
  • kernel-core RHEL 10.1 6.12.0-124.35.1.el10_1

red hat advisories RHSA-2026:2282RHSA-2026:1727

  • kernel-rt Linux Micro 6.2 6.12.0-160000.8.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.8.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.8.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.8.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.8.1.160000.2.5
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.8.1
  • kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.8.1
  • kernel-kvmsmall SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.8.1

suse advisories SUSE-SU-2026:20012-1SUSE-SU-2026:20015-1SUSE-SU-2026:20021-1SUSE-SU-2026:20562-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.8.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.8.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.8.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.8.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.8.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.8.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.8.1
  • kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.8.1

opensuse advisories openSUSE-SU-2025:20172-1

  • kernel-abi-stablelists AlmaLinux 10 6.12.0-124.35.1.el10_1

almalinux advisories ALSA-2026:2282

  • kernel Rocky Linux 10 6.12.0-124.35.1.el10_1

rocky linux advisories RLSA-2026:2282

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-2025-40133 updated cvss 7.0

kernel: mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable()

  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-124.35.1.el10_1, perf 6.12.0-124.35.1.el10_1, rtla 6.12.0-124.35.1.el10_1, python3-perf 6.12.0-124.35.1.el10_1, kernel-devel-matched 6.12.0-124.35.1.el10_1, kernel-64k-devel-matched 6.12.0-124.35.1.el10_1, +7 more
    fixed: vendor fix RHSA-2026:2282
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) rv 6.12.0-55.58.1.el10_0, perf 6.12.0-55.58.1.el10_0, rtla 6.12.0-55.58.1.el10_0, python3-perf 6.12.0-55.58.1.el10_0, kernel-devel-matched 6.12.0-55.58.1.el10_0, kernel-64k-devel-matched 6.12.0-55.58.1.el10_0, +7 more
    fixed: vendor fix RHSA-2026:1727
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-124.35.1.el10_1, kernel-64k 6.12.0-124.35.1.el10_1, kernel-core 6.12.0-124.35.1.el10_1, kernel-tools 6.12.0-124.35.1.el10_1, kernel-modules 6.12.0-124.35.1.el10_1, kernel-64k-core 6.12.0-124.35.1.el10_1, +28 more
    fixed: vendor fix RHSA-2026:2282
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel 6.12.0-55.58.1.el10_0, kernel-64k 6.12.0-55.58.1.el10_0, kernel-core 6.12.0-55.58.1.el10_0, kernel-tools 6.12.0-55.58.1.el10_0, kernel-modules 6.12.0-55.58.1.el10_0, kernel-64k-core 6.12.0-55.58.1.el10_0, +27 more
    fixed: vendor fix RHSA-2026:1727
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-124.35.1.el10_1, kernel-debuginfo-common-s390x 6.12.0-124.35.1.el10_1, kernel-debuginfo-common-x86_64 6.12.0-124.35.1.el10_1, kernel-debuginfo-common-aarch64 6.12.0-124.35.1.el10_1, kernel-debuginfo-common-ppc64le 6.12.0-124.35.1.el10_1
    fixed: vendor fix RHSA-2026:2282
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) libperf 6.12.0-55.58.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.58.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.58.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.58.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.58.1.el10_0
    fixed: vendor fix RHSA-2026:1727
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-124.35.1.el10_1, kernel-rt-64k 6.12.0-124.35.1.el10_1, kernel-rt-core 6.12.0-124.35.1.el10_1, kernel-rt-modules 6.12.0-124.35.1.el10_1, kernel-rt-64k-core 6.12.0-124.35.1.el10_1, kernel-rt-debug-core 6.12.0-124.35.1.el10_1, +14 more
    fixed: vendor fix RHSA-2026:2282
  • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt 6.12.0-55.58.1.el10_0, kernel-rt-64k 6.12.0-55.58.1.el10_0, kernel-rt-core 6.12.0-55.58.1.el10_0, kernel-rt-modules 6.12.0-55.58.1.el10_0, kernel-rt-64k-core 6.12.0-55.58.1.el10_0, kernel-rt-debug-core 6.12.0-55.58.1.el10_0, +14 more
    fixed: vendor fix RHSA-2026:1727
show 3 more
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-124.35.1.el10_1, kernel-rt-core 6.12.0-124.35.1.el10_1, kernel-rt-modules 6.12.0-124.35.1.el10_1, kernel-rt-debug-core 6.12.0-124.35.1.el10_1, kernel-rt-modules-core 6.12.0-124.35.1.el10_1, kernel-rt-debug-modules 6.12.0-124.35.1.el10_1, +4 more
    fixed: vendor fix RHSA-2026:2282
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt 6.12.0-55.58.1.el10_0, kernel-rt-kvm 6.12.0-55.58.1.el10_0, kernel-rt-core 6.12.0-55.58.1.el10_0, kernel-rt-modules 6.12.0-55.58.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.58.1.el10_0, kernel-rt-debug-core 6.12.0-55.58.1.el10_0, +6 more
    fixed: vendor fix RHSA-2026:1727
  • 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

0.51% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

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.