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Fencer Intel
high 7.5

CVE-2025-71132 json

smc91x: fix broken irq-context in PREEMPT_RT

published 9mo ago modified 21d ago also EUVD-2026-2483

cvss
7.5
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 12%
public exploits
0
none known

Summary

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

smc91x: fix broken irq-context in PREEMPT_RT

When smc91x.c is built with PREEMPT_RT, the following splat occurs in FVP_RevC:

[ 13.055000] smc91x LNRO0003:00 eth0: link up, 10Mbps, half-duplex, lpa 0x0000 [ 13.062137] BUG: workqueue leaked atomic, lock or RCU: kworker/2:1[106] [ 13.062137] preempt=0x00000000 lock=0->0 RCU=0->1 workfn=mld_ifc_work [ 13.062266] C ** replaying previous printk message ** [ 13.062266] CPU: 2 UID: 0 PID: 106 Comm: kworker/2:1 Not tainted 6.18.0-dirty #179 PREEMPT_{RT,(full)} [ 13.062353] Hardware name: , BIOS [ 13.062382] Workqueue: mld mld_ifc_work [ 13.062469] Call trace: [ 13.062494] show_stack+0x24/0x40 (C) [ 13.062602] __dump_stack+0x28/0x48 [ 13.062710] dump_stack_lvl+0x7c/0xb0 [ 13.062818] dump_stack+0x18/0x34 [ 13.062926] process_scheduled_works+0x294/0x450 [ 13.063043] worker_thread+0x260/0x3d8 [ 13.063124] kthread+0x1c4/0x228 [ 13.063235] ret_from_fork+0x10/0x20

This happens because smc_special_trylock() disables IRQs even on PREEMPT_RT, but smc_special_unlock() does not restore IRQs on PREEMPT_RT. The reason is that smc_special_unlock() calls spin_unlock_irqrestore(), and rcu_read_unlock_bh() in __dev_queue_xmit() cannot invoke rcu_read_unlock() through __local_bh_enable_ip() when current->softirq_disable_cnt becomes zero.

To address this issue, replace smc_special_trylock() with spin_trylock_irqsave().

Patch / fix

  • Linux Linux 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.4, 6.19
  • linux Debian 12 6.1.162-1
  • linux Debian 13 6.12.69-1
  • linux Debian 14 6.18.5-1

debian advisories DEBIAN-CVE-2025-71132

  • linux Ubuntu 22.04 LTS 5.15.0-173.183
  • linux Ubuntu 24.04 LTS 6.8.0-110.110
  • linux Ubuntu 25.10 6.17.0-22.22
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1103.110
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1052.55
  • linux-aws Ubuntu 25.10 6.17.0-1012.12
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1103.112
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1054.57

ubuntu advisories UBUNTU-CVE-2025-71132

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 4.18.0-553.159.1.el8_10
  • perf RHEL 8 4.18.0-553.159.1.el8_10
  • bpftool RHEL 8 4.18.0-553.159.1.el8_10
  • kernel-core RHEL 8 4.18.0-553.159.1.el8_10
  • kernel-tools RHEL 8 4.18.0-553.159.1.el8_10
  • python3-perf RHEL 8 4.18.0-553.159.1.el8_10
  • kernel-modules RHEL 8 4.18.0-553.159.1.el8_10
  • kernel-zfcpdump RHEL 8 4.18.0-553.159.1.el8_10

red hat advisories RHSA-2026:63014RHSA-2026:63013

  • kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
  • kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
  • kernel-rt Linux Micro 6.2 6.12.0-160000.26.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.26.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.26.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.26.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.26.1.160000.2.7
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.26.1

suse advisories SUSE-SU-2026:20845-1SUSE-SU-2026:20876-1SUSE-SU-2026:20555-1SUSE-SU-2026:20599-1SUSE-SU-2026:20615-1SUSE-SU-2026:20570-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.26.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.26.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.26.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.26.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.26.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.26.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.26.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.26.1

opensuse advisories openSUSE-SU-2026:20287-1

  • kernel-rt AlmaLinux 8 4.18.0-553.159.1.rt7.500.el8_10
  • kernel-rt-core AlmaLinux 8 4.18.0-553.159.1.rt7.500.el8_10
  • kernel-rt-modules AlmaLinux 8 4.18.0-553.159.1.rt7.500.el8_10
  • kernel-rt-debug-core AlmaLinux 8 4.18.0-553.159.1.rt7.500.el8_10
  • kernel-rt-debug-modules AlmaLinux 8 4.18.0-553.159.1.rt7.500.el8_10
  • kernel-rt-modules-extra AlmaLinux 8 4.18.0-553.159.1.rt7.500.el8_10
  • kernel-rt-debug-modules-extra AlmaLinux 8 4.18.0-553.159.1.rt7.500.el8_10
  • kernel AlmaLinux 8 4.18.0-553.159.1.el8_10

almalinux advisories ALSA-2026:63013ALSA-2026:63014

  • kernel-rt Rocky Linux 8 4.18.0-553.159.1.rt7.500.el8_10
  • kernel Rocky Linux 8 4.18.0-553.159.1.el8_10

rocky linux advisories RLSA-2026:63013RLSA-2026:63014

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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-2025-71132 updated cvss 4.7

kernel: smc91x: fix broken irq-context in PREEMPT_RT

  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.159.1.el8_10, kernel 4.18.0-553.159.1.el8_10, bpftool 4.18.0-553.159.1.el8_10, kernel-core 4.18.0-553.159.1.el8_10, kernel-tools 4.18.0-553.159.1.el8_10, python3-perf 4.18.0-553.159.1.el8_10, +15 more Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.159.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.159.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.159.1.el8_10
    fixed: vendor fix RHSA-2026:63014
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-kvm 4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-core 4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-modules 4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-debug-kvm 4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-debug-core 4.18.0-553.159.1.rt7.500.el8_10, +4 more Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-core 4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-modules 4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-debug-core 4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-debug-modules 4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-modules-extra 4.18.0-553.159.1.rt7.500.el8_10, +2 more
    fixed: vendor fix RHSA-2026:63013
  • 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
partial
Assessed
4mo ago

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-09).

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
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

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel 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.