CVE-2026-23115: serial: Fix not set tty->port race condition

Q: What access and conditions are required to trigger this issue?

The CVSS vector indicates local access, low privileges, no user interaction, and high attack complexity. The race occurs when user space can open a serial console before the TTY has been linked to its driver port.

Q: Which deployments are most likely to encounter the race?

The reported reproduction was on a Qualcomm SoC during very fast boot, with most devices disabled and one serial device configured as the console. The issue is specifically associated with serial-console initialization timing.

Q: How can I identify a potentially affected system?

Affected systems may log a warning such as “ttyMSM driver does not set tty->port” from tty_init_dev. The warning states that the condition could crash the kernel, so unexpected boot-time warnings or crashes involving serial-console initialization are relevant indicators.

Published Feb 14, 2026

Updated

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

serial: Fix not set tty->port race condition

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

This ttyportlinkdevice() 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 [qcomgeni0] disabled printk: legacy bootconsole [qcomgeni0] disabled ------------[ cut here ]------------ ttyinitdev: ttyMSM driver does not set tty->port. This would crash the kernel. Fix the driver! WARNING: drivers/tty/ttyio.c:1414 at ttyinitdev.part.0+0x228/0x25c, CPU#2: systemd/1 Modules linked in: socinfo tcsrcceliza gcceliza sm3ce 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]=CPUOUTOFSPEC Hardware name: Qualcomm Technologies, Inc. Eliza (DT) ... ttyinitdev.part.0 (drivers/tty/ttyio.c:1414 (discriminator 11)) (P) ttyopen (arch/arm64/include/asm/atomicllsc.h:95 (discriminator 3) drivers/tty/ttyio.c:2073 (discriminator 3) drivers/tty/ttyio.c:2120 (discriminator 3)) chrdevopen (fs/chardev.c:411) dodentryopen (fs/open.c:962) vfsopen (fs/open.c:1094) doopen (fs/namei.c:4634) pathopenat (fs/namei.c:4793) dofilpopen (fs/namei.c:4820) dosysopenat2 (fs/open.c:1391 (discriminator 3)) ... Starting Network Name Resolution...

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

driver (qcomgeniserial.c): user-space: ============================ =========== qcomgeniserialprobe() uartaddoneport() serialcoreregisterport() serialcoreaddoneport() uartconfigureport() registerconsole() | | open console | ... | ttyinitdev() | driver->ports[idx] is NULL | ttyportregisterdeviceattrserdev() ttyportlinkdevice() <- set driver->ports[idx]

Affected Software

8 affected components

Linux Linux kernel

Linux Linux kernel>=6.15<6.18.8

Linux Linux kernel=6.19-rc1

Linux Linux kernel=6.19-rc2

Linux Linux kernel=6.19-rc3

Linux Linux kernel=6.19-rc4

Linux Linux kernel=6.19-rc5

Linux Linux kernel=6.19-rc6

Event History

Feb 14, 2026

CVE Published

via MITRE·03:09 PM

Data Sourced

via MITRE·03:09 PM

Description

Data Sourced

via NVD·03:16 PM

RemedyDescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

What access and conditions are required to trigger this issue?

The CVSS vector indicates local access, low privileges, no user interaction, and high attack complexity. The race occurs when user space can open a serial console before the TTY has been linked to its driver port.

Which deployments are most likely to encounter the race?

The reported reproduction was on a Qualcomm SoC during very fast boot, with most devices disabled and one serial device configured as the console. The issue is specifically associated with serial-console initialization timing.

How can I identify a potentially affected system?

Affected systems may log a warning such as “ttyMSM driver does not set tty->port” from tty_init_dev. The warning states that the condition could crash the kernel, so unexpected boot-time warnings or crashes involving serial-console initialization are relevant indicators.

What is the corrective change?

The resolution restores tty_port_link_device() so tty->port is configured before uart_configure_port() is called. The provided stable kernel references contain the resolved changes.

CVE-2026-23115: serial: Fix not set tty->port race condition

Affected Software

Event History

Frequently Asked Questions

What access and conditions are required to trigger this issue?

Which deployments are most likely to encounter the race?

How can I identify a potentially affected system?

What is the corrective change?

Company

Resources

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Frequently Asked Questions

What access and conditions are required to trigger this issue?

Which deployments are most likely to encounter the race?

How can I identify a potentially affected system?

What is the corrective change?