CVE-2026-93123

serial: qcom-geni: do not advance stale DMA completions

Published Sep 17, 2026 CVSS n/a EPSS < 1% KEV · Not listed

Description

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

serial: qcom-geni: do not advance stale DMA completions

The qcom GENI serial DMA TX completion path advances the transmit fifo by
the number of bytes recorded in port->tx_remaining.

If uart_flush_buffer() runs after the hardware has completed a DMA
transfer but before the DMA completion interrupt has been handled, the
serial core resets the transmit fifo while port->tx_remaining still
describes the old DMA transfer.

A previous fix avoided advancing an empty fifo by checking that the fifo
length is at least tx_remaining. That still does not distinguish the old
DMA payload from new bytes written after the flush. If userspace writes
new data before the stale DMA completion interrupt is handled, the fifo
can again contain at least tx_remaining bytes and the stale completion
can advance and discard those new bytes.

Mark an in-flight DMA transfer stale when the transmit fifo is flushed.
The later completion still unprepares the original DMA mapping using the
saved length, but it no longer advances the transmit fifo.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`2aaa43c7077833301c237684cd7bc9ae5e3dec95`	affected	< 231c84fe7ec40e4a06c398c0591d5b8e823d68e1
`2aaa43c7077833301c237684cd7bc9ae5e3dec95`	affected	< c02d030747c46da33faf406dd772ef91100efa27
`2aaa43c7077833301c237684cd7bc9ae5e3dec95`	affected	< 59faa59c25a0a098fbc86275408d7c8405015702
`2aaa43c7077833301c237684cd7bc9ae5e3dec95`	affected	< 7ea38c49e7178960926657863299face6dc0e1b0

Linux

affected

Version	Status	Constraints
`6.3`	affected	—
`0`	unaffected	< 6.3
`6.12.110`	unaffected	≤ 6.12.*
`6.18.52`	unaffected	≤ 6.18.*
`7.2.6`	unaffected	≤ 7.2.*
`7.3`	unaffected	≤ *

No data.

Vendor Product Versions

Linux

Linux Kernel

Version	Status	Scheme	Platform
`[2aaa43c7077833301c237684cd7bc9ae5e3dec95,231c84fe7ec40e4a06c398c0591d5b8e823d68e1)`	affected	code_commit	—
`[2aaa43c7077833301c237684cd7bc9ae5e3dec95,c02d030747c46da33faf406dd772ef91100efa27)`	affected	code_commit	—
`[2aaa43c7077833301c237684cd7bc9ae5e3dec95,59faa59c25a0a098fbc86275408d7c8405015702)`	affected	code_commit	—
`[2aaa43c7077833301c237684cd7bc9ae5e3dec95,7ea38c49e7178960926657863299face6dc0e1b0)`	affected	code_commit	—

Linux

Linux Kernel

Version	Status	Scheme	Platform
`6.3`	affected	semver	—
`[0,6.3)`	unaffected	semver	—
`[6.12.110,6.13.0)`	unaffected	semver	—
`[6.18.52,6.19.0)`	unaffected	semver	—
`[7.2.6,7.3.0)`	unaffected	semver	—
`[7.3-rc1,*]`	unaffected	semver	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

Source	ID	Title
Debian DLA	DLA-4817-1	linux-6.12 security update
Debian DSA	DSA-6528-1	linux security update
Ubuntu USN	USN-9019-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-9020-1	Linux kernel vulnerabilities

Metrics

No CVSS v4.0

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.209% probability within 30 days)

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/231c84fe7ec40e4a06c398c0591d5b8e823d68e1
https://git.kernel.org/stable/c/59faa59c25a0a098fbc86275408d7c8405015702
https://git.kernel.org/stable/c/7ea38c49e7178960926657863299face6dc0e1b0
https://git.kernel.org/stable/c/c02d030747c46da33faf406dd772ef91100efa27

History

Sep 19, 2026 7:30 AM Weaknesses updated View changes

Type	Values Removed	Values Added
Weaknesses		CWE-365

Sep 17, 2026 4:30 PM Description updated. Title updated. First appearance in the feed. Affected versions updated. Affected vendors updated. Added references View changes

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: serial: qcom-geni: do not advance stale DMA completions The qcom GENI serial DMA TX completion path advances the transmit fifo by the number of bytes recorded in port->tx_remaining. If uart_flush_buffer() runs after the hardware has completed a DMA transfer but before the DMA completion interrupt has been handled, the serial core resets the transmit fifo while port->tx_remaining still describes the old DMA transfer. A previous fix avoided advancing an empty fifo by checking that the fifo length is at least tx_remaining. That still does not distinguish the old DMA payload from new bytes written after the flush. If userspace writes new data before the stale DMA completion interrupt is handled, the fifo can again contain at least tx_remaining bytes and the stale completion can advance and discard those new bytes. Mark an in-flight DMA transfer stale when the transmit fifo is flushed. The later completion still unprepares the original DMA mapping using the saved length, but it no longer advances the transmit fifo.
Title		serial: qcom-geni: do not advance stale DMA completions
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/231c84fe7ec40e4a06c398c0591d5b8e823d68e1 https://git.kernel.org/stable/c/59faa59c25a0a098fbc86275408d7c8405015702 https://git.kernel.org/stable/c/7ea38c49e7178960926657863299face6dc0e1b0 https://git.kernel.org/stable/c/c02d030747c46da33faf406dd772ef91100efa27