CVE-2026-98751: tty: abort break signalling on hangup
In the Linux kernel, the following vulnerability has been resolved:
tty: abort break signalling on hangup
The break ioctls can race with hangup and end up calling into a tty driver for a device that is already gone or powered down.
Drivers must handle this race, but TCSBRK and TCSBRKP should still be aborted to avoid calling back into the driver after a user-controlled timeout (possibly even after the tty has been reopened).
Note that drivers should disable any break state on shutdown so just return on hangup (calling breakctl() again is racy and will most likely fail for drivers handling the race).
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.12.113-1 - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 7.2.10-1 - Upgrade
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debian/linux-6.12to a version that resolves this vulnerability.Fixed in 6.12.113-1~deb12u1 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 5.10.273 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 5.15.224 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.1.191 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.6.160 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.12.113 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.18.56 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 7.2.10 - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1 - Upgrade
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azurelinux/kernelto a version that resolves this vulnerability.Fixed in 6.6.161.1-1 - Compensating control
Update tty drivers to abort TCSBRK and TCSBRKP on hangup, disable any break state on shutdown, and return immediately on hangup without calling break_ctl() again.
Event History
Frequently Asked Questions
What conditions are needed to trigger this issue?
A process must issue the TCSBRK or TCSBRKP break ioctl while the associated TTY is being hung up. The race can otherwise allow a delayed callback into a driver after the device has gone away or been powered down, including after a user-controlled timeout.
Which systems are realistically exposed?
Linux systems using TTY devices and drivers are relevant when applications can invoke TCSBRK or TCSBRKP concurrently with device hangup. The provided information does not identify particular TTY drivers or configurations.
What behavior does the fix introduce?
The fix aborts pending break signalling when hangup occurs, rather than calling the driver again. Drivers are expected to disable any break state during shutdown; attempting another break_ctl() call during hangup is described as racy and likely to fail.