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

serial: Fix not set tty->port race condition

Revert commit bfc467db60b7 ("serial: remove redundant
tty_port_link_device()") because the tty_port_link_device() is not
redundant: the tty->port has to be confured before we call
uart_configure_port(), otherwise user-space can open console without TTY
linked to the driver.

This tty_port_link_device() was added explicitly to avoid this exact
issue in commit fb2b90014d78 ("tty: link tty and port before configuring
it as console"), so offending commit basically reverted the fix saying
it is redundant without addressing the actual race condition presented
there.

Reproducible always as tty->port warning on Qualcomm SoC with most of
devices disabled, so with very fast boot, and one serial device being
the console:

printk: legacy console [ttyMSM0] enabled
printk: legacy console [ttyMSM0] enabled
printk: legacy bootconsole [qcom_geni0] disabled
printk: legacy bootconsole [qcom_geni0] disabled
------------[ cut here ]------------
tty_init_dev: ttyMSM driver does not set tty->port. This would crash the kernel. Fix the driver!
WARNING: drivers/tty/tty_io.c:1414 at tty_init_dev.part.0+0x228/0x25c, CPU#2: systemd/1
Modules linked in: socinfo tcsrcc_eliza gcc_eliza sm3_ce fuse ipv6
CPU: 2 UID: 0 PID: 1 Comm: systemd Tainted: G S 6.19.0-rc4-next-20260108-00024-g2202f4d30aa8 #73 PREEMPT
Tainted: [S]=CPU_OUT_OF_SPEC
Hardware name: Qualcomm Technologies, Inc. Eliza (DT)
...
tty_init_dev.part.0 (drivers/tty/tty_io.c:1414 (discriminator 11)) (P)
tty_open (arch/arm64/include/asm/atomic_ll_sc.h:95 (discriminator 3) drivers/tty/tty_io.c:2073 (discriminator 3) drivers/tty/tty_io.c:2120 (discriminator 3))
chrdev_open (fs/char_dev.c:411)
do_dentry_open (fs/open.c:962)
vfs_open (fs/open.c:1094)
do_open (fs/namei.c:4634)
path_openat (fs/namei.c:4793)
do_filp_open (fs/namei.c:4820)
do_sys_openat2 (fs/open.c:1391 (discriminator 3))
...
Starting Network Name Resolution...

Apparently the flow with this small Yocto-based ramdisk user-space is:

driver (qcom_geni_serial.c): user-space:
============================ ===========
qcom_geni_serial_probe()
uart_add_one_port()
serial_core_register_port()
serial_core_add_one_port()
uart_configure_port()
register_console()
|
| open console
| ...
| tty_init_dev()
| driver->ports[idx] is NULL
|
tty_port_register_device_attr_serdev()
tty_port_link_device() <- set driver->ports[idx]
Published: 2026-02-14
Score: 4.7 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Denial of Service (Kernel Crash)
Action: Update Kernel
AI Analysis

Impact

The race condition is triggered when tty_port_link_device is omitted before uart_configure_port, allowing a user‑space process to open the serial console during the boot sequence. The kernel then attempts to initialize the console with an uninitialized tty->port reference, which causes an immediate kernel panic. This soft‑fail path results in a local denial‑of‑service that requires no network involvement but demands the ability to access the console device, typically root or a privileged user. The flaw is a classic example of a race condition (CWE‑362).

Affected Systems

The bug is present in the Linux kernel 6.19 release series before the recent commit that re‑established tty_port_link_device. The affected releases are the rc1 through rc6 snapshots and any downstream patches that did not cherry‑pick the fix. Devices that use a Qualcomm SoC with a serial port configured as the boot console are the most likely to hit the error, but any system that links a serial console without first setting tty->port is vulnerable. The vulnerability applies to the generic Linux kernel; there is no vendor‑specific product beyond the kernel itself.

Risk and Exploitability

With a CVSS base score of 4.7 the vulnerability poses moderate impact; the availability metric is high. The EPSS score of less than 1 % indicates a low probability of exploitation, and the feature is not listed in the CISA KEV catalog. The attack vector is local user space. An attacker with the ability to open the console device during the very early boot phase can trigger the race and force the kernel to crash, disrupting all services. Because the condition is self‑applied at boot, it does not enable privilege escalation or data theft; the result is limited to denial‑of‑service.

Generated by OpenCVE AI on April 17, 2026 at 19:45 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade the Linux kernel to a release that incorporates the patch restoring tty_port_link_device before uart_configure_port
  • For custom drivers, verify that the console initialization order links the TTY device before calling uart_configure_port or any console registration functions
  • As a temporary mitigation, remove the serial port from the kernel command line console= option or disable console access on that device until the kernel is updated

Generated by OpenCVE AI on April 17, 2026 at 19:45 UTC.

Tracking

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Advisories

No advisories yet.

History

Wed, 18 Mar 2026 13:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362
CPEs cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.19:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.19:rc6:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'}


Tue, 17 Feb 2026 00:15:00 +0000


Sat, 14 Feb 2026 15:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: serial: Fix not set tty->port race condition Revert commit bfc467db60b7 ("serial: remove redundant tty_port_link_device()") because the tty_port_link_device() is not redundant: the tty->port has to be confured before we call uart_configure_port(), otherwise user-space can open console without TTY linked to the driver. This tty_port_link_device() was added explicitly to avoid this exact issue in commit fb2b90014d78 ("tty: link tty and port before configuring it as console"), so offending commit basically reverted the fix saying it is redundant without addressing the actual race condition presented there. Reproducible always as tty->port warning on Qualcomm SoC with most of devices disabled, so with very fast boot, and one serial device being the console: printk: legacy console [ttyMSM0] enabled printk: legacy console [ttyMSM0] enabled printk: legacy bootconsole [qcom_geni0] disabled printk: legacy bootconsole [qcom_geni0] disabled ------------[ cut here ]------------ tty_init_dev: ttyMSM driver does not set tty->port. This would crash the kernel. Fix the driver! WARNING: drivers/tty/tty_io.c:1414 at tty_init_dev.part.0+0x228/0x25c, CPU#2: systemd/1 Modules linked in: socinfo tcsrcc_eliza gcc_eliza sm3_ce fuse ipv6 CPU: 2 UID: 0 PID: 1 Comm: systemd Tainted: G S 6.19.0-rc4-next-20260108-00024-g2202f4d30aa8 #73 PREEMPT Tainted: [S]=CPU_OUT_OF_SPEC Hardware name: Qualcomm Technologies, Inc. Eliza (DT) ... tty_init_dev.part.0 (drivers/tty/tty_io.c:1414 (discriminator 11)) (P) tty_open (arch/arm64/include/asm/atomic_ll_sc.h:95 (discriminator 3) drivers/tty/tty_io.c:2073 (discriminator 3) drivers/tty/tty_io.c:2120 (discriminator 3)) chrdev_open (fs/char_dev.c:411) do_dentry_open (fs/open.c:962) vfs_open (fs/open.c:1094) do_open (fs/namei.c:4634) path_openat (fs/namei.c:4793) do_filp_open (fs/namei.c:4820) do_sys_openat2 (fs/open.c:1391 (discriminator 3)) ... Starting Network Name Resolution... Apparently the flow with this small Yocto-based ramdisk user-space is: driver (qcom_geni_serial.c): user-space: ============================ =========== qcom_geni_serial_probe() uart_add_one_port() serial_core_register_port() serial_core_add_one_port() uart_configure_port() register_console() | | open console | ... | tty_init_dev() | driver->ports[idx] is NULL | tty_port_register_device_attr_serdev() tty_port_link_device() <- set driver->ports[idx]
Title serial: Fix not set tty->port race condition
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-02-14T15:09:47.826Z

Reserved: 2026-01-13T15:37:45.969Z

Link: CVE-2026-23115

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2026-02-14T15:16:06.607

Modified: 2026-03-18T13:41:27.780

Link: CVE-2026-23115

cve-icon Redhat

Severity :

Publid Date: 2026-02-14T00:00:00Z

Links: CVE-2026-23115 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-17T19:45:25Z

Weaknesses