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Fencer Vulns
high 7.5

CVE-2026-64048 json

net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot

published 2026-07-19 3 mo ago modified 2026-10-19 20 d ago also EUVD-2026-45621

cvss
7.5
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 43%
public exploits
0
none known

Summary

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

net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot

On the SMC-D client, slot 0 of ini->ism_dev[]/ini->ism_chid[] is reserved for an SMC-Dv1 device. smc_find_ism_v2_device_clnt() populates V2 entries starting at index 1, so when no V1 device is selected slot 0 is left in its kzalloc()'ed state with ism_dev[0] == NULL and ism_chid[0] == 0.

smc_v2_determine_accepted_chid() then matches the peer's CHID against the array starting from index 0 using the CHID alone. A malicious peer replying to a SMC-Dv2-only proposal with d1.chid == 0 matches the empty slot, ini->ism_selected becomes 0, and the subsequent ism_dev[0]->lgr_lock dereference in smc_conn_create() faults at offsetof(struct smcd_dev, lgr_lock) == 0x68:

BUG: KASAN: null-ptr-deref in _raw_spin_lock_bh+0x79/0xe0 Write of size 4 at addr 0000000000000068 by task exploit/144 Call Trace: _raw_spin_lock_bh smc_conn_create (net/smc/smc_core.c:1997) __smc_connect (net/smc/af_smc.c:1447) smc_connect (net/smc/af_smc.c:1720) __sys_connect __x64_sys_connect do_syscall_64

Require ism_dev[i] to be non-NULL before accepting a CHID match.

Patch / fix

  • Linux Linux 5.10.266, 5.15.217, 6.1.175, 6.6.142, 6.12.92, 6.18.34, 7.0.11, 7.1
  • linux Debian 12 6.1.176-1
  • linux Debian 13 6.12.94-1
  • linux Debian 14 7.0.12-1

debian advisories DEBIAN-CVE-2026-64048

  • linux Ubuntu 22.04 LTS 5.15.0-202.212
  • linux Ubuntu 24.04 LTS 6.8.0-139.139
  • linux Ubuntu 26.04 LTS 7.0.0-28.28
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1119.126
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1064.67
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1009.9
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1120.130
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1067.75

ubuntu advisories UBUNTU-CVE-2026-64048

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 8 4.18.0-553.157.1.el8_10
  • perf RHEL 8 4.18.0-553.157.1.el8_10
  • bpftool RHEL 8 4.18.0-553.157.1.el8_10
  • kernel-core RHEL 8 4.18.0-553.157.1.el8_10
  • kernel-tools RHEL 8 4.18.0-553.157.1.el8_10
  • python3-perf RHEL 8 4.18.0-553.157.1.el8_10
  • kernel-modules RHEL 8 4.18.0-553.157.1.el8_10
  • kernel-zfcpdump RHEL 8 4.18.0-553.157.1.el8_10

red hat advisories RHSA-2026:57253RHSA-2026:57254RHSA-2026:57252

  • kernel-64kb SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS, SLE High Performance Computing 15 SP5-ESPOS 5.14.21-150500.55.189.1
  • kernel-syms SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.189.1
  • kernel-source SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 5.14.21-150500.55.189.1
  • kernel-default SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +3 more 5.14.21-150500.55.189.1
  • kernel-obs-build SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.189.1
  • kernel-default-base SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 5.14.21-150500.55.189.1.150500.6.87.4
  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.81.1

suse advisories SUSE-SU-2026:4595-1SUSE-SU-2026:4254-1SUSE-SU-2026:4369-1SUSE-SU-2026:4347-1SUSE-SU-2026:4284-1SUSE-SU-2026:23887-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.38.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.38.1

opensuse advisories openSUSE-SU-2026:21910-1

  • kernel AlmaLinux 10 6.12.0-211.68.1.el10_2
  • rv AlmaLinux 10 6.12.0-211.68.1.el10_2
  • perf AlmaLinux 10 6.12.0-211.68.1.el10_2
  • rtla AlmaLinux 10 6.12.0-211.68.1.el10_2
  • libperf AlmaLinux 10 6.12.0-211.68.1.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.68.1.el10_2
  • kernel-64k AlmaLinux 10 6.12.0-211.68.1.el10_2
  • kernel-core AlmaLinux 10 6.12.0-211.68.1.el10_2

almalinux advisories ALSA-2026:88477ALSA-2026:57252ALSA-2026:57253ALSA-2026:57254

  • kernel Rocky Linux 10 6.12.0-211.68.1.el10_2
  • kernel Rocky Linux 9 5.14.0-687.41.1.el9_8
  • kernel-rt Rocky Linux 8 4.18.0-553.157.1.rt7.498.el8_10
  • kernel Rocky Linux 8 4.18.0-553.157.1.el8_10

rocky linux advisories RLSA-2026:88477RLSA-2026:57252RLSA-2026:57254RLSA-2026:57253

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-2026-64048 updated cvss 7.5

kernel: net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot

  • 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 Enterprise Linux kernel-modules-internal 6.12.0-211.68.1.el10_2
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.41.1.el9_8, perf 5.14.0-687.41.1.el9_8, rtla 5.14.0-687.41.1.el9_8, python3-perf 5.14.0-687.41.1.el9_8, kernel-devel-matched 5.14.0-687.41.1.el9_8, kernel-64k-devel-matched 5.14.0-687.41.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:57252
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.68.1.el10_2, perf 6.12.0-211.68.1.el10_2, rtla 6.12.0-211.68.1.el10_2, python3-perf 6.12.0-211.68.1.el10_2, kernel-devel-matched 6.12.0-211.68.1.el10_2, kernel-64k-devel-matched 6.12.0-211.68.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.157.1.el8_10, kernel 4.18.0-553.157.1.el8_10, bpftool 4.18.0-553.157.1.el8_10, kernel-core 4.18.0-553.157.1.el8_10, kernel-tools 4.18.0-553.157.1.el8_10, python3-perf 4.18.0-553.157.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:57253
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.41.1.el9_8, kernel-64k 5.14.0-687.41.1.el9_8, kernel-core 5.14.0-687.41.1.el9_8, kernel-tools 5.14.0-687.41.1.el9_8, kernel-modules 5.14.0-687.41.1.el9_8, kernel-64k-core 5.14.0-687.41.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:57252
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.68.1.el10_2, kernel-64k 6.12.0-211.68.1.el10_2, kernel-core 6.12.0-211.68.1.el10_2, kernel-tools 6.12.0-211.68.1.el10_2, kernel-modules 6.12.0-211.68.1.el10_2, kernel-64k-core 6.12.0-211.68.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.41.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.41.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.41.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.41.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.41.1.el9_8
    fixed: vendor fix RHSA-2026:57252
show 10 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.68.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.68.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.68.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.68.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.68.1.el10_2
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.157.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.157.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.157.1.el8_10
    fixed: vendor fix RHSA-2026:57253
  • Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.68.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.68.1.el10_2
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-kvm 4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-core 4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-modules 4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-debug-kvm 4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-debug-core 4.18.0-553.157.1.rt7.498.el8_10, +4 more
    fixed: vendor fix RHSA-2026:57254
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.41.1.el9_8, kernel-rt-64k 5.14.0-687.41.1.el9_8, kernel-rt-core 5.14.0-687.41.1.el9_8, kernel-rt-modules 5.14.0-687.41.1.el9_8, kernel-rt-64k-core 5.14.0-687.41.1.el9_8, kernel-rt-debug-core 5.14.0-687.41.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:57252
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.68.1.el10_2, kernel-rt-64k 6.12.0-211.68.1.el10_2, kernel-rt-core 6.12.0-211.68.1.el10_2, kernel-rt-modules 6.12.0-211.68.1.el10_2, kernel-rt-64k-core 6.12.0-211.68.1.el10_2, kernel-rt-debug-core 6.12.0-211.68.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.41.1.el9_8, kernel-rt-core 5.14.0-687.41.1.el9_8, kernel-rt-modules 5.14.0-687.41.1.el9_8, kernel-rt-debug-core 5.14.0-687.41.1.el9_8, kernel-rt-modules-core 5.14.0-687.41.1.el9_8, kernel-rt-debug-modules 5.14.0-687.41.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:57252
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.68.1.el10_2, kernel-rt-core 6.12.0-211.68.1.el10_2, kernel-rt-modules 6.12.0-211.68.1.el10_2, kernel-rt-debug-core 6.12.0-211.68.1.el10_2, kernel-rt-modules-core 6.12.0-211.68.1.el10_2, kernel-rt-debug-modules 6.12.0-211.68.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-core 4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-modules 4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-debug-core 4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-debug-modules 4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-modules-extra 4.18.0-553.157.1.rt7.498.el8_10, +2 more
    fixed: vendor fix RHSA-2026:57254
  • 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
yes
Technical impact
partial
Assessed
23 d ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

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.