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Fencer Vulns
high 8.4

CVE-2025-39718 json

vsock/virtio: Validate length in packet header before skb_put()

published 2025-09-05 14 mo ago modified 2026-10-19 20 d ago also EUVD-2025-31509

cvss
8.4
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 6%
public exploits
0
none known

Summary

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

vsock/virtio: Validate length in packet header before skb_put()

When receiving a vsock packet in the guest, only the virtqueue buffer size is validated prior to virtio_vsock_skb_rx_put(). Unfortunately, virtio_vsock_skb_rx_put() uses the length from the packet header as the length argument to skb_put(), potentially resulting in SKB overflow if the host has gone wonky.

Validate the length as advertised by the packet header before calling virtio_vsock_skb_rx_put().

Patch / fix

  • Linux Linux 6.1.149, 6.6.103, 6.12.44, 6.16.4, 6.17
  • Siemens SIMATIC CN 4100 V5.0
  • linux Debian 12 6.1.153-1
  • linux Debian 13 6.12.48-1
  • linux Debian 14 6.16.5-1

debian advisories DEBIAN-CVE-2025-39718

  • linux Ubuntu 24.04 LTS 6.8.0-100.100
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1046.49
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1047.50
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1043.48
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1044.44
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1046.52
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1030.33
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1047.51

ubuntu advisories UBUNTU-CVE-2025-39718

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-rt RHEL 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-kvm RHEL 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-core RHEL 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-modules RHEL 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-debug-kvm RHEL 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-debug-core RHEL 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-debug-modules RHEL 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-modules-extra RHEL 8 4.18.0-553.84.1.rt7.425.el8_10

red hat advisories RHSA-2025:21397RHSA-2025:21398RHSA-2025:21118RHSA-2025:21112RHSA-2025:19106RHSA-2025:19105

  • 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-2025:21179-1SUSE-SU-2025:20870-1SUSE-SU-2025:20898-1

  • 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-rt AlmaLinux 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-core AlmaLinux 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-modules AlmaLinux 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-debug-core AlmaLinux 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-debug-modules AlmaLinux 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-modules-extra AlmaLinux 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel-rt-debug-modules-extra AlmaLinux 8 4.18.0-553.84.1.rt7.425.el8_10
  • kernel AlmaLinux 8 4.18.0-553.84.1.el8_10

almalinux advisories ALSA-2025:21397ALSA-2025:21398

  • kernel Rocky Linux 9 5.14.0-570.58.1.el9_6
  • kernel Rocky Linux 10 6.12.0-55.41.1.el10_0

rocky linux advisories RLSA-2025:19105RLSA-2025:19106

  • kernel Azure Linux 3.0 6.6.104.2-1

azure linux advisories AZL-66947

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-2025-39718 updated cvss 7.6

kernel: vsock/virtio: Validate length in packet header before skb_put()

  • 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: workaround, no fix available
  • Red Hat CodeReady Linux Builder EUS (v.9.4) libperf 5.14.0-427.96.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.96.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.96.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.96.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.96.1.el9_4
    fixed: vendor fix RHSA-2025:19104
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-611.7.1.el9_7, rv 5.14.0-570.58.1.el9_6, perf 5.14.0-611.7.1.el9_7, rtla 5.14.0-611.7.1.el9_7, perf 5.14.0-570.58.1.el9_6, rtla 5.14.0-570.58.1.el9_6, +20 more
    fixed: vendor fix RHSA-2025:19105
  • 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
    fixed: vendor fix RHSA-2025:19106
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) rv 5.14.0-427.96.1.el9_4, perf 5.14.0-427.96.1.el9_4, rtla 5.14.0-427.96.1.el9_4, kernel-devel-matched 5.14.0-427.96.1.el9_4, kernel-64k-devel-matched 5.14.0-427.96.1.el9_4, kernel-debug-devel-matched 5.14.0-427.96.1.el9_4, +6 more
    fixed: vendor fix RHSA-2025:19104
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.84.1.el8_10, kernel 4.18.0-553.84.1.el8_10, bpftool 4.18.0-553.84.1.el8_10, kernel-core 4.18.0-553.84.1.el8_10, kernel-tools 4.18.0-553.84.1.el8_10, python3-perf 4.18.0-553.84.1.el8_10, +15 more
    fixed: vendor fix RHSA-2025:21398
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-611.7.1.el9_7, kernel 5.14.0-570.58.1.el9_6, kernel-64k 5.14.0-611.7.1.el9_7, kernel-64k 5.14.0-570.58.1.el9_6, kernel-core 5.14.0-611.7.1.el9_7, kernel-core 5.14.0-570.58.1.el9_6, +60 more
    fixed: vendor fix RHSA-2025:19105
  • 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
    fixed: vendor fix RHSA-2025:19106
show 13 more
  • Red Hat Enterprise Linux BaseOS EUS (v.9.4) bpftool 7.3.0-427.96.1.el9_4, kernel 5.14.0-427.96.1.el9_4, kernel-64k 5.14.0-427.96.1.el9_4, kernel-core 5.14.0-427.96.1.el9_4, kernel-tools 5.14.0-427.96.1.el9_4, python3-perf 5.14.0-427.96.1.el9_4, +28 more
    fixed: vendor fix RHSA-2025:19104
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-611.7.1.el9_7, libperf 5.14.0-570.58.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-611.7.1.el9_7, kernel-debuginfo-common-s390x 5.14.0-570.58.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-611.7.1.el9_7, kernel-debuginfo-common-aarch64 5.14.0-611.7.1.el9_7, +4 more
    fixed: vendor fix RHSA-2025:19105
  • 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
    fixed: vendor fix RHSA-2025:19106
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.84.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.84.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.84.1.el8_10
    fixed: vendor fix RHSA-2025:21398
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.84.1.rt7.425.el8_10, kernel-rt-kvm 4.18.0-553.84.1.rt7.425.el8_10, kernel-rt-core 4.18.0-553.84.1.rt7.425.el8_10, kernel-rt-modules 4.18.0-553.84.1.rt7.425.el8_10, kernel-rt-debug-kvm 4.18.0-553.84.1.rt7.425.el8_10, kernel-rt-debug-core 4.18.0-553.84.1.rt7.425.el8_10, +4 more
    fixed: vendor fix RHSA-2025:21397
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-611.7.1.el9_7, kernel-rt 5.14.0-570.58.1.el9_6, kernel-rt-64k 5.14.0-611.7.1.el9_7, kernel-rt-64k 5.14.0-570.58.1.el9_6, kernel-rt-core 5.14.0-611.7.1.el9_7, kernel-rt-core 5.14.0-570.58.1.el9_6, +34 more
    fixed: vendor fix RHSA-2025:19105
  • 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
    fixed: vendor fix RHSA-2025:19106
  • Red Hat Enterprise Linux Real Time EUS (v.9.4) kernel-rt 5.14.0-427.96.1.el9_4, kernel-rt-core 5.14.0-427.96.1.el9_4, kernel-rt-modules 5.14.0-427.96.1.el9_4, kernel-rt-debug-core 5.14.0-427.96.1.el9_4, kernel-rt-modules-core 5.14.0-427.96.1.el9_4, kernel-rt-debug-modules 5.14.0-427.96.1.el9_4, +4 more
    fixed: vendor fix RHSA-2025:19104
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-611.7.1.el9_7, kernel-rt 5.14.0-570.58.1.el9_6, kernel-rt-core 5.14.0-611.7.1.el9_7, kernel-rt-kvm 5.14.0-570.58.1.el9_6, kernel-rt-core 5.14.0-570.58.1.el9_6, kernel-rt-modules 5.14.0-611.7.1.el9_7, +16 more
    fixed: vendor fix RHSA-2025:19105
  • 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 Real Time for NFV EUS (v.9.4) kernel-rt 5.14.0-427.96.1.el9_4, kernel-rt-kvm 5.14.0-427.96.1.el9_4, kernel-rt-core 5.14.0-427.96.1.el9_4, kernel-rt-modules 5.14.0-427.96.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.96.1.el9_4, kernel-rt-debug-core 5.14.0-427.96.1.el9_4, +6 more
    fixed: vendor fix RHSA-2025:19104
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.84.1.rt7.425.el8_10, kernel-rt-core 4.18.0-553.84.1.rt7.425.el8_10, kernel-rt-modules 4.18.0-553.84.1.rt7.425.el8_10, kernel-rt-debug-core 4.18.0-553.84.1.rt7.425.el8_10, kernel-rt-debug-modules 4.18.0-553.84.1.rt7.425.el8_10, kernel-rt-modules-extra 4.18.0-553.84.1.rt7.425.el8_10, +2 more
    fixed: vendor fix RHSA-2025:21397
  • 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
    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
24 d ago

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.4 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux
  • Siemens SIMATIC CN 4100

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.