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Fencer Vulns
critical 9.8

CVE-2026-31607 in the critical feed json

usbip: validate number_of_packets in usbip_pack_ret_submit()

published 2026-04-24 6 mo ago modified 2026-10-19 20 d ago also EUVD-2026-25500

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

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

usbip: validate number_of_packets in usbip_pack_ret_submit()

When a USB/IP client receives a RET_SUBMIT response, usbip_pack_ret_submit() unconditionally overwrites urb->number_of_packets from the network PDU. This value is subsequently used as the loop bound in usbip_recv_iso() and usbip_pad_iso() to iterate over urb->iso_frame_desc[], a flexible array whose size was fixed at URB allocation time based on the *original* number_of_packets from the CMD_SUBMIT.

A malicious USB/IP server can set number_of_packets in the response to a value larger than what was originally submitted, causing a heap out-of-bounds write when usbip_recv_iso() writes to urb->iso_frame_desc[i] beyond the allocated region.

KASAN confirmed this with kernel 7.0.0-rc5:

BUG: KASAN: slab-out-of-bounds in usbip_recv_iso+0x46a/0x640 Write of size 4 at addr ffff888106351d40 by task vhci_rx/69

The buggy address is located 0 bytes to the right of allocated 320-byte region [ffff888106351c00, ffff888106351d40)

The server side (stub_rx.c) and gadget side (vudc_rx.c) already validate number_of_packets in the CMD_SUBMIT path since commits c6688ef9f297 ("usbip: fix stub_rx: harden CMD_SUBMIT path to handle malicious input") and b78d830f0049 ("usbip: fix vudc_rx: harden CMD_SUBMIT path to handle malicious input"). The server side validates against USBIP_MAX_ISO_PACKETS because no URB exists yet at that point. On the client side we have the original URB, so we can use the tighter bound: the response must not exceed the original number_of_packets.

This mirrors the existing validation of actual_length against transfer_buffer_length in usbip_recv_xbuff(), which checks the response value against the original allocation size.

Kelvin Mbogo's series ("usb: usbip: fix integer overflow in usbip_recv_iso()", v2) hardens the receive-side functions themselves; this patch complements that work by catching the bad value at its source -- in usbip_pack_ret_submit() before the overwrite -- and using the tighter per-URB allocation bound rather than the global USBIP_MAX_ISO_PACKETS limit.

Fix this by checking rpdu->number_of_packets against urb->number_of_packets in usbip_pack_ret_submit() before the overwrite. On violation, clamp to zero so that usbip_recv_iso() and usbip_pad_iso() safely return early.

Patch / fix

  • Linux Linux 2.6.33, 2.6.34, 2.6.35, 2.6.36, 2.6.39, 5.10.258, 5.15.209, 6.1.175, 6.6.136, 6.12.83, 6.18.24, 6.19.14, 7.0.1, 7.1
  • Red Hat Red Hat Enterprise Linux 10 0:6.12.0-211.16.1.el10_2
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 0:6.12.0-55.77.1.el10_0
  • Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support 0:3.10.0-1160.151.1.el7, 0:3.10.0-1160.155.1.rt56.1307.el7
  • Red Hat Red Hat Enterprise Linux 9 0:5.14.0-687.10.1.el9_8
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support 0:5.14.0-570.119.1.el9_6
  • linux Debian 12 6.1.176-1
  • linux Debian 13 6.12.85-1
  • linux Debian 14 6.19.14-1

debian advisories DEBIAN-CVE-2026-31607

  • linux Ubuntu 22.04 LTS 5.15.0-185.195
  • linux Ubuntu 24.04 LTS 6.8.0-134.134
  • linux Ubuntu 25.10 6.17.0-40.40
  • linux Ubuntu 26.04 LTS 7.0.0-27.27
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1111.118
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1060.63
  • linux-aws Ubuntu 25.10 6.17.0-1019.19
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1008.8

ubuntu advisories UBUNTU-CVE-2026-31607

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 6.12.0-211.16.1.el10_2
  • rv RHEL 10.2 6.12.0-211.16.1.el10_2
  • perf RHEL 10.2 6.12.0-211.16.1.el10_2
  • rtla RHEL 10.2 6.12.0-211.16.1.el10_2
  • libperf RHEL 10.2 6.12.0-211.16.1.el10_2
  • kernel-rt RHEL 10.2 6.12.0-211.16.1.el10_2
  • kernel-64k RHEL 10.2 6.12.0-211.16.1.el10_2
  • kernel-core RHEL 10.2 6.12.0-211.16.1.el10_2

red hat advisories RHSA-2026:41236RHSA-2026:25095RHSA-2026:24343RHSA-2026:23224RHSA-2026:19569RHSA-2026:19568

  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.37.1
  • kernel-rt Linux Micro 6.2 6.12.0-160000.37.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1.160000.2.19
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1
  • kernel-azure SLES 16.0, SLES for SAP applications 16.0 6.12.0-160000.37.1
  • kernel-obs-qa SLES 16.0, SLES for SAP applications 16.0 6.12.0-160000.37.1

suse advisories SUSE-SU-2026:23237-1SUSE-SU-2026:23068-1SUSE-SU-2026:23221-1SUSE-SU-2026:23231-1SUSE-SU-2026:23066-1SUSE-SU-2026:2195-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.37.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.37.1

opensuse advisories openSUSE-SU-2026:21555-1openSUSE-SU-2026:10703-1

  • kernel AlmaLinux 9 5.14.0-687.10.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.10.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.10.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.10.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.10.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.10.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.10.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.10.1.el9_8

almalinux advisories ALSA-2026:19568ALSA-2026:19569

  • kernel Rocky Linux 10 6.12.0-211.16.1.el10_2.0.1
  • kernel Rocky Linux 9 5.14.0-687.10.1.el9_8.0.1

rocky linux advisories RLSA-2026:19569RLSA-2026:19568

  • kernel Azure Linux 3.0 6.6.137.1-1

azure linux advisories AZL-83642

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-2026-31607 updated cvss 7.3

kernel: usbip: validate number_of_packets in usbip_pack_ret_submit()

  • 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.9.6) libperf 5.14.0-570.119.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.119.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.119.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.119.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.119.1.el9_6
    fixed: vendor fix RHSA-2026:23224
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.10.1.el9_8, perf 5.14.0-687.10.1.el9_8, rtla 5.14.0-687.10.1.el9_8, python3-perf 5.14.0-687.10.1.el9_8, kernel-devel-matched 5.14.0-687.10.1.el9_8, kernel-64k-devel-matched 5.14.0-687.10.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:19568
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.16.1.el10_2, perf 6.12.0-211.16.1.el10_2, rtla 6.12.0-211.16.1.el10_2, python3-perf 6.12.0-211.16.1.el10_2, kernel-devel-matched 6.12.0-211.16.1.el10_2, kernel-64k-devel-matched 6.12.0-211.16.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:19569
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) rv 6.12.0-55.77.1.el10_0, perf 6.12.0-55.77.1.el10_0, rtla 6.12.0-55.77.1.el10_0, python3-perf 6.12.0-55.77.1.el10_0, kernel-devel-matched 6.12.0-55.77.1.el10_0, kernel-64k-devel-matched 6.12.0-55.77.1.el10_0, +7 more
    fixed: vendor fix RHSA-2026:24343
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) rv 5.14.0-570.119.1.el9_6, perf 5.14.0-570.119.1.el9_6, rtla 5.14.0-570.119.1.el9_6, python3-perf 5.14.0-570.119.1.el9_6, kernel-devel-matched 5.14.0-570.119.1.el9_6, kernel-64k-devel-matched 5.14.0-570.119.1.el9_6, +7 more
    fixed: vendor fix RHSA-2026:23224
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.10.1.el9_8, kernel-64k 5.14.0-687.10.1.el9_8, kernel-core 5.14.0-687.10.1.el9_8, kernel-tools 5.14.0-687.10.1.el9_8, kernel-modules 5.14.0-687.10.1.el9_8, kernel-64k-core 5.14.0-687.10.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:19568
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.16.1.el10_2, kernel-64k 6.12.0-211.16.1.el10_2, kernel-core 6.12.0-211.16.1.el10_2, kernel-tools 6.12.0-211.16.1.el10_2, kernel-modules 6.12.0-211.16.1.el10_2, kernel-64k-core 6.12.0-211.16.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:19569
show 16 more
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel 6.12.0-55.77.1.el10_0, kernel-64k 6.12.0-55.77.1.el10_0, kernel-core 6.12.0-55.77.1.el10_0, kernel-tools 6.12.0-55.77.1.el10_0, kernel-modules 6.12.0-55.77.1.el10_0, kernel-64k-core 6.12.0-55.77.1.el10_0, +27 more
    fixed: vendor fix RHSA-2026:24343
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel 5.14.0-570.119.1.el9_6, kernel-64k 5.14.0-570.119.1.el9_6, kernel-core 5.14.0-570.119.1.el9_6, kernel-tools 5.14.0-570.119.1.el9_6, kernel-modules 5.14.0-570.119.1.el9_6, kernel-64k-core 5.14.0-570.119.1.el9_6, +27 more
    fixed: vendor fix RHSA-2026:23224
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.10.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.10.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.10.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.10.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.10.1.el9_8
    fixed: vendor fix RHSA-2026:19568
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.16.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.16.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.16.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.16.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.16.1.el10_2
    fixed: vendor fix RHSA-2026:19569
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) libperf 6.12.0-55.77.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.77.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.77.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.77.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.77.1.el10_0
    fixed: vendor fix RHSA-2026:24343
  • Red Hat Enterprise Linux for Real Time (v. 7 ELS) kernel-rt 3.10.0-1160.155.1.rt56.1307.el7, kernel-rt-trace 3.10.0-1160.155.1.rt56.1307.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-1160.155.1.rt56.1307.el7
    fixed: vendor fix RHSA-2026:41236
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.10.1.el9_8, kernel-rt-64k 5.14.0-687.10.1.el9_8, kernel-rt-core 5.14.0-687.10.1.el9_8, kernel-rt-modules 5.14.0-687.10.1.el9_8, kernel-rt-64k-core 5.14.0-687.10.1.el9_8, kernel-rt-debug-core 5.14.0-687.10.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:19568
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.16.1.el10_2, kernel-rt-64k 6.12.0-211.16.1.el10_2, kernel-rt-core 6.12.0-211.16.1.el10_2, kernel-rt-modules 6.12.0-211.16.1.el10_2, kernel-rt-64k-core 6.12.0-211.16.1.el10_2, kernel-rt-debug-core 6.12.0-211.16.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:19569
  • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt 6.12.0-55.77.1.el10_0, kernel-rt-64k 6.12.0-55.77.1.el10_0, kernel-rt-core 6.12.0-55.77.1.el10_0, kernel-rt-modules 6.12.0-55.77.1.el10_0, kernel-rt-64k-core 6.12.0-55.77.1.el10_0, kernel-rt-debug-core 6.12.0-55.77.1.el10_0, +14 more
    fixed: vendor fix RHSA-2026:24343
  • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt 5.14.0-570.119.1.el9_6, kernel-rt-64k 5.14.0-570.119.1.el9_6, kernel-rt-core 5.14.0-570.119.1.el9_6, kernel-rt-modules 5.14.0-570.119.1.el9_6, kernel-rt-64k-core 5.14.0-570.119.1.el9_6, kernel-rt-debug-core 5.14.0-570.119.1.el9_6, +14 more
    fixed: vendor fix RHSA-2026:23224
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.10.1.el9_8, kernel-rt-core 5.14.0-687.10.1.el9_8, kernel-rt-modules 5.14.0-687.10.1.el9_8, kernel-rt-debug-core 5.14.0-687.10.1.el9_8, kernel-rt-modules-core 5.14.0-687.10.1.el9_8, kernel-rt-debug-modules 5.14.0-687.10.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:19568
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.16.1.el10_2, kernel-rt-core 6.12.0-211.16.1.el10_2, kernel-rt-modules 6.12.0-211.16.1.el10_2, kernel-rt-debug-core 6.12.0-211.16.1.el10_2, kernel-rt-modules-core 6.12.0-211.16.1.el10_2, kernel-rt-debug-modules 6.12.0-211.16.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:19569
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt 6.12.0-55.77.1.el10_0, kernel-rt-kvm 6.12.0-55.77.1.el10_0, kernel-rt-core 6.12.0-55.77.1.el10_0, kernel-rt-modules 6.12.0-55.77.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.77.1.el10_0, kernel-rt-debug-core 6.12.0-55.77.1.el10_0, +6 more
    fixed: vendor fix RHSA-2026:24343
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt 5.14.0-570.119.1.el9_6, kernel-rt-kvm 5.14.0-570.119.1.el9_6, kernel-rt-core 5.14.0-570.119.1.el9_6, kernel-rt-modules 5.14.0-570.119.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.119.1.el9_6, kernel-rt-debug-core 5.14.0-570.119.1.el9_6, +6 more
    fixed: vendor fix RHSA-2026:23224
  • Red Hat Enterprise Linux Server (v. 7 ELS) perf 3.10.0-1160.151.1.el7, kernel 3.10.0-1160.151.1.el7, bpftool 3.10.0-1160.151.1.el7, python-perf 3.10.0-1160.151.1.el7, kernel-kdump 3.10.0-1160.151.1.el7, kernel-tools 3.10.0-1160.151.1.el7, +7 more Red Hat Enterprise Linux Server Optional (v. 7 ELS) kernel-debuginfo-common-ppc64 3.10.0-1160.151.1.el7, kernel-debuginfo-common-x86_64 3.10.0-1160.151.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-1160.151.1.el7
    fixed: vendor fix RHSA-2026:25095
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 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
yes
Technical impact
total
Assessed
24 d ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADP 3.1 7.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
CNA 3.1 7.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H

Affected products

  • Linux Linux
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 8

Classification

Weakness
  • CWE-805 Buffer Access with Incorrect Length Value
  • CWE-787 Out-of-bounds Write
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.