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Fencer Vulns
medium 5.5

CVE-2024-46706 json

tty: serial: fsl_lpuart: mark last busy before uart_add_one_port

published 2024-09-13 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-41967

cvss
5.5
version 3.1, NVD
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:

tty: serial: fsl_lpuart: mark last busy before uart_add_one_port

With "earlycon initcall_debug=1 loglevel=8" in bootargs, kernel sometimes boot hang. It is because normal console still is not ready, but runtime suspend is called, so early console putchar will hang in waiting TRDE set in UARTSTAT.

The lpuart driver has auto suspend delay set to 3000ms, but during uart_add_one_port, a child device serial ctrl will added and probed with its pm runtime enabled(see serial_ctrl.c). The runtime suspend call path is: device_add |-> bus_probe_device |->device_initial_probe |->__device_attach |-> pm_runtime_get_sync(dev->parent); |-> pm_request_idle(dev); |-> pm_runtime_put(dev->parent);

So in the end, before normal console ready, the lpuart get runtime suspended. And earlycon putchar will hang.

To address the issue, mark last busy just after pm_runtime_enable, three seconds is long enough to switch from bootconsole to normal console.

Patch / fix

  • Linux Linux 6.6.48, 6.10.7, 6.11
  • linux Debian 14, Debian 13 6.10.7-1

debian advisories DEBIAN-CVE-2024-46706

  • linux Ubuntu 24.04 LTS 6.8.0-50.51
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1020.22
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1019.21
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1015.19
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1017.17
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1020.23
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1002.4
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1016.18

ubuntu advisories UBUNTU-CVE-2024-46706

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-rt Linux Micro 6.0 6.4.0-11.1
  • kernel-source-rt Linux Micro 6.0 6.4.0-11.1
  • kernel-livepatch-MICRO-6-0-RT_Update_3 Linux Micro 6.0 1-1.2
  • kernel-source Linux Micro 6.0 6.4.0-20.1
  • kernel-default Linux Micro 6.0 6.4.0-20.1
  • kernel-kvmsmall Linux Micro 6.0 6.4.0-20.1
  • kernel-default-base Linux Micro 6.0 6.4.0-17.1.1.51
  • kernel-livepatch-MICRO-6-0_Update_3 Linux Micro 6.0 1-1.2

suse advisories SUSE-SU-2025:20077-1SUSE-SU-2025:20073-1SUSE-SU-2024:3564-1SUSE-SU-2024:3561-1SUSE-SU-2024:3553-1SUSE-SU-2024:3551-1

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-2024-46706 updated cvss 4.0

kernel: tty: serial: fsl_lpuart: mark last busy before uart_add_one_port

  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    affected: workaround, no fix available “Fix deferred”
  • 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
    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
2 y ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
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

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.