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Fencer Vulns
high 7.5

CVE-2026-46031 json

net: ks8851: Reinstate disabling of BHs around IRQ handler

published 2026-05-27 5 mo ago modified 2026-08-05 3 mo ago also EUVD-2026-32412

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

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

net: ks8851: Reinstate disabling of BHs around IRQ handler

If the driver executes ks8851_irq() AND a TX packet has been sent, then the driver enables TX queue via netif_wake_queue() which schedules TX softirq to queue packets for this device.

If CONFIG_PREEMPT_RT=y is set AND a packet has also been received by the MAC, then ks8851_rx_pkts() calls netdev_alloc_skb_ip_align() to allocate SKBs for the received packets. If netdev_alloc_skb_ip_align() is called with BH enabled, then local_bh_enable() at the end of netdev_alloc_skb_ip_align() will trigger the pending softirq processing, which may ultimately call the .xmit callback ks8851_start_xmit_par(). The ks8851_start_xmit_par() will try to lock struct ks8851_net_par .lock spinlock, which is already locked by ks8851_irq() from which ks8851_start_xmit_par() was called. This leads to a deadlock, which is reported by the kernel, including a trace listed below.

If CONFIG_PREEMPT_RT is not set, then since commit 0913ec336a6c0 ("net: ks8851: Fix deadlock with the SPI chip variant") the deadlock can also be triggered without received packet in the RX FIFO. The pending softirqs will be processed on return from spin_unlock_bh(&ks->statelock) in ks8851_irq(), which triggers the deadlock as well.

Fix the problem by disabling BH around critical sections, including the IRQ handler, thus preventing the net_tx_action() softirq from triggering during these critical sections. The net_tx_action() softirq is triggered once BH are re-enabled and at the end of the IRQ handler, once all the other IRQ handler actions have been completed.

__schedule from schedule_rtlock+0x1c/0x34 schedule_rtlock from rtlock_slowlock_locked+0x548/0x904 rtlock_slowlock_locked from rt_spin_lock+0x60/0x9c rt_spin_lock from ks8851_start_xmit_par+0x74/0x1a8 ks8851_start_xmit_par from netdev_start_xmit+0x20/0x44 netdev_start_xmit from dev_hard_start_xmit+0xd0/0x188 dev_hard_start_xmit from sch_direct_xmit+0xb8/0x25c sch_direct_xmit from __qdisc_run+0x1f8/0x4ec __qdisc_run from qdisc_run+0x1c/0x28 qdisc_run from net_tx_action+0x1f0/0x268 net_tx_action from handle_softirqs+0x1a4/0x270 handle_softirqs from __local_bh_enable_ip+0xcc/0xe0 __local_bh_enable_ip from __alloc_skb+0xd8/0x128 __alloc_skb from __netdev_alloc_skb+0x3c/0x19c __netdev_alloc_skb from ks8851_irq+0x388/0x4d4 ks8851_irq from irq_thread_fn+0x24/0x64 irq_thread_fn from irq_thread+0x178/0x28c irq_thread from kthread+0x12c/0x138 kthread from ret_from_fork+0x14/0x28

Patch / fix

  • Linux Linux 6.1.175, 6.6.140, 6.9, 6.12.86, 6.18.27, 7.0.4, 7.1
  • linux Debian 12 6.1.176-1
  • linux Debian 13 6.12.86-1
  • linux Debian 14 7.0.4-1

debian advisories DEBIAN-CVE-2026-46031

  • linux Ubuntu 24.04 LTS 6.8.0-136.136
  • linux Ubuntu 26.04 LTS 7.0.0-27.27
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1008.8
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1007.7
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1059.67
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1061.62

ubuntu advisories UBUNTU-CVE-2026-46031

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-source openSUSE Tumbleweed 7.0.11-1.1

opensuse advisories openSUSE-SU-2026:10954-1

  • kernel Azure Linux 3.0 6.6.141.1-1

azure linux advisories AZL-88731

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-2026-46031 updated

kernel: net: ks8851: Reinstate disabling of BHs around IRQ handler

  • 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 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    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

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% 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.