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Fencer Vulns
high 7.8

CVE-2026-31474 json

can: isotp: fix tx.buf use-after-free in isotp_sendmsg()

published 2026-04-22 6 mo ago modified 2026-10-19 20 d ago also EUVD-2026-24827

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

Summary

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

can: isotp: fix tx.buf use-after-free in isotp_sendmsg()

isotp_sendmsg() uses only cmpxchg() on so->tx.state to serialize access to so->tx.buf. isotp_release() waits for ISOTP_IDLE via wait_event_interruptible() and then calls kfree(so->tx.buf).

If a signal interrupts the wait_event_interruptible() inside close() while tx.state is ISOTP_SENDING, the loop exits early and release proceeds to force ISOTP_SHUTDOWN and continues to kfree(so->tx.buf) while sendmsg may still be reading so->tx.buf for the final CAN frame in isotp_fill_dataframe().

The so->tx.buf can be allocated once when the standard tx.buf length needs to be extended. Move the kfree() of this potentially extended tx.buf to sk_destruct time when either isotp_sendmsg() and isotp_release() are done.

Patch / fix

  • Linux Linux 6.6.131, 6.12.80, 6.18.21, 6.19.11, 7.0
  • Red Hat Red Hat Enterprise Linux 10 0:6.12.0-211.26.1.el10_2
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 0:6.12.0-55.82.1.el10_0
  • Red Hat Red Hat Enterprise Linux 9 0:5.14.0-687.17.1.el9_8
  • linux Debian 13 6.12.85-1
  • linux Debian 14 6.19.11-1

debian advisories DEBIAN-CVE-2026-31474

  • linux Ubuntu 24.04 LTS 6.8.0-136.136
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1059.67
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1061.62
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1063.71
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1046.50
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1061.65

ubuntu advisories UBUNTU-CVE-2026-31474

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 9 5.14.0-687.17.1.el9_8
  • rv RHEL 9 5.14.0-687.17.1.el9_8
  • perf RHEL 9 5.14.0-687.17.1.el9_8
  • rtla RHEL 9 5.14.0-687.17.1.el9_8
  • libperf RHEL 9 5.14.0-687.17.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.17.1.el9_8
  • kernel-64k RHEL 9 5.14.0-687.17.1.el9_8
  • kernel-core RHEL 9 5.14.0-687.17.1.el9_8

red hat advisories RHSA-2026:27789RHSA-2026:27731RHSA-2026:27288

  • kernel-source Linux Micro 6.1, Linux Micro 6.0 6.4.0-51.1
  • kernel-default Linux Micro 6.1, Linux Micro 6.0 6.4.0-51.1
  • kernel-kvmsmall Linux Micro 6.1, Linux Micro 6.0 6.4.0-51.1
  • kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-51.1
  • kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-51.1
  • 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

suse advisories SUSE-SU-2026:23244-1SUSE-SU-2026:23241-1SUSE-SU-2026:23194-1SUSE-SU-2026:23193-1SUSE-SU-2026:23237-1SUSE-SU-2026:23068-1

  • 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-2026:21555-1

  • kernel AlmaLinux 9 5.14.0-687.17.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.17.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.17.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.17.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.17.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.17.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.17.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.17.1.el9_8

almalinux advisories ALSA-2026:27789ALSA-2026:27288

  • kernel Rocky Linux 9 5.14.0-687.17.1.el9_8
  • kernel Rocky Linux 10 6.12.0-211.26.1.el10_2

rocky linux advisories RLSA-2026:27789RLSA-2026:27288

  • kernel Azure Linux 3.0 6.6.134.1-2

azure linux advisories AZL-83225

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-2026-31474 updated cvss 7.8

kernel: can: isotp: fix tx.buf use-after-free in isotp_sendmsg()

  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.17.1.el9_8, perf 5.14.0-687.17.1.el9_8, rtla 5.14.0-687.17.1.el9_8, python3-perf 5.14.0-687.17.1.el9_8, kernel-devel-matched 5.14.0-687.17.1.el9_8, kernel-64k-devel-matched 5.14.0-687.17.1.el9_8, +7 more
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27789
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.26.1.el10_2, perf 6.12.0-211.26.1.el10_2, rtla 6.12.0-211.26.1.el10_2, python3-perf 6.12.0-211.26.1.el10_2, kernel-devel-matched 6.12.0-211.26.1.el10_2, kernel-64k-devel-matched 6.12.0-211.26.1.el10_2, +7 more
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27288
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) rv 6.12.0-55.82.1.el10_0, perf 6.12.0-55.82.1.el10_0, rtla 6.12.0-55.82.1.el10_0, python3-perf 6.12.0-55.82.1.el10_0, kernel-devel-matched 6.12.0-55.82.1.el10_0, kernel-64k-devel-matched 6.12.0-55.82.1.el10_0, +7 more
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27731
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.17.1.el9_8, kernel-64k 5.14.0-687.17.1.el9_8, kernel-core 5.14.0-687.17.1.el9_8, kernel-tools 5.14.0-687.17.1.el9_8, kernel-modules 5.14.0-687.17.1.el9_8, kernel-64k-core 5.14.0-687.17.1.el9_8, +27 more
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27789
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.26.1.el10_2, kernel-64k 6.12.0-211.26.1.el10_2, kernel-core 6.12.0-211.26.1.el10_2, kernel-tools 6.12.0-211.26.1.el10_2, kernel-modules 6.12.0-211.26.1.el10_2, kernel-64k-core 6.12.0-211.26.1.el10_2, +28 more
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27288
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel 6.12.0-55.82.1.el10_0, kernel-64k 6.12.0-55.82.1.el10_0, kernel-core 6.12.0-55.82.1.el10_0, kernel-tools 6.12.0-55.82.1.el10_0, kernel-modules 6.12.0-55.82.1.el10_0, kernel-64k-core 6.12.0-55.82.1.el10_0, +27 more
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27731
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.17.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.17.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.17.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.17.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.17.1.el9_8
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27789
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.26.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.26.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.26.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.26.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.26.1.el10_2
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27288
show 8 more
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) libperf 6.12.0-55.82.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.82.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.82.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.82.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.82.1.el10_0
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27731
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.17.1.el9_8, kernel-rt-64k 5.14.0-687.17.1.el9_8, kernel-rt-core 5.14.0-687.17.1.el9_8, kernel-rt-modules 5.14.0-687.17.1.el9_8, kernel-rt-64k-core 5.14.0-687.17.1.el9_8, kernel-rt-debug-core 5.14.0-687.17.1.el9_8, +14 more
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27789
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.26.1.el10_2, kernel-rt-64k 6.12.0-211.26.1.el10_2, kernel-rt-core 6.12.0-211.26.1.el10_2, kernel-rt-modules 6.12.0-211.26.1.el10_2, kernel-rt-64k-core 6.12.0-211.26.1.el10_2, kernel-rt-debug-core 6.12.0-211.26.1.el10_2, +14 more
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27288
  • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt 6.12.0-55.82.1.el10_0, kernel-rt-64k 6.12.0-55.82.1.el10_0, kernel-rt-core 6.12.0-55.82.1.el10_0, kernel-rt-modules 6.12.0-55.82.1.el10_0, kernel-rt-64k-core 6.12.0-55.82.1.el10_0, kernel-rt-debug-core 6.12.0-55.82.1.el10_0, +14 more
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27731
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.17.1.el9_8, kernel-rt-core 5.14.0-687.17.1.el9_8, kernel-rt-modules 5.14.0-687.17.1.el9_8, kernel-rt-debug-core 5.14.0-687.17.1.el9_8, kernel-rt-modules-core 5.14.0-687.17.1.el9_8, kernel-rt-debug-modules 5.14.0-687.17.1.el9_8, +4 more
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27789
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.26.1.el10_2, kernel-rt-core 6.12.0-211.26.1.el10_2, kernel-rt-modules 6.12.0-211.26.1.el10_2, kernel-rt-debug-core 6.12.0-211.26.1.el10_2, kernel-rt-modules-core 6.12.0-211.26.1.el10_2, kernel-rt-debug-modules 6.12.0-211.26.1.el10_2, +4 more
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27288
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt 6.12.0-55.82.1.el10_0, kernel-rt-kvm 6.12.0-55.82.1.el10_0, kernel-rt-core 6.12.0-55.82.1.el10_0, kernel-rt-modules 6.12.0-55.82.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.82.1.el10_0, kernel-rt-debug-core 6.12.0-55.82.1.el10_0, +6 more
    fixed: vendor fix “Systems which do not require it can blocklist the `can_isotp` module to prevent it from being loaded. See https://access.redhat.com/solutions/41278 for more information.” RHSA-2026:27731
  • 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 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 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
23 d ago

Exploit prediction

0.10% chance of exploitation in the next 30 days, higher than 1% 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

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 9
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8

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.